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B1 adverb #2,000 پرکاربردترین 10 دقیقه مطالعه

いずれ

izure رتبه 2,000

At the A1 level, you can think of いずれ (Izure) as a slightly more formal way to say 'one day' or 'later.' While A1 learners usually focus on simple time words like 'ashita' (tomorrow) or 'kyou' (today), learning いずれ helps you understand that some things in Japanese don't have a fixed time. You might hear it in very simple phrases like 'いずれまた' (See you again). At this stage, just remember that it points to the future, but not a specific day. It is like saying 'not now, but later.' You don't need to worry about the complex grammar yet; just recognize it as a word that means 'eventually.' It is often used when people want to be polite and not promise a specific time that they might forget. For example, if someone asks 'When will you visit Japan?' and you don't know, you can say 'いずれ' to mean 'someday.'

For A2 learners, いずれ (Izure) becomes useful for making simple predictions or plans. You are starting to build longer sentences, and いずれ helps you connect current actions to future results. You might use it with verbs like 'wakaru' (to understand) or 'dekiru' (to be able to do). A common sentence at this level would be 'いずれ分かります' (You will understand eventually). This shows you understand that some things take time. You should also start to notice the difference between いずれ and 'itsuka.' Remember that いずれ sounds a bit more certain. If you are studying hard, you can say 'いずれ日本語が上手になります' (I will eventually become good at Japanese). This sounds more determined than using 'itsuka.' You are also likely to encounter 'いずれにしても' in simple reading passages, meaning 'anyway' or 'in any case.'

At the B1 level, you should be able to use いずれ (Izure) to add nuance and formality to your speech and writing. This is the level where you transition from basic communication to more natural, adult-like Japanese. You should use いずれ in business emails or formal discussions to refer to future events without being overly specific. For example, 'いずれ詳しくお話しします' (I will talk to you in detail eventually). You should also master the phrase 'いずれにしても' to synthesize arguments. At B1, you are expected to understand that いずれ implies a logical inevitability. It's not just a random 'someday'; it's a 'sooner or later' that is bound to happen because of the current situation. You can use it to express confidence in a project's success or to warn someone about the consequences of their actions. It is a key word for expressing professional maturity.

B2 learners should have a firm grasp of the various functions of いずれ (Izure), including its less common role as a formal pronoun meaning 'which.' You should be able to distinguish between the adverbial use ('eventually') and the pronominal use ('which one') based on context. In writing, you can use いずれ to create a sense of rhythm and sophistication. For instance, using it at the beginning of a paragraph to set a long-term perspective. You should also be comfortable with its use in news reports and editorials, where it often appears in discussions about social trends or economic forecasts. At this level, you should also understand the literary nuance of いずれ in novels, where it can create a sense of foreshadowing or fate. You are moving beyond just 'knowing' the word to 'feeling' its weight in different registers of the language.

At the C1 level, your use of いずれ (Izure) should be indistinguishable from a native speaker's. You understand the subtle historical baggage the word carries from its classical roots. You can use it in high-level academic writing to discuss philosophical concepts of time or in legal contexts where 'いずれか' (either/any) is used to define options precisely. You are also aware of how いずれ can be used to soften a statement or make it more indirect, which is a hallmark of advanced Japanese social intelligence. You can use it to navigate complex social hierarchies, where being too specific about time might be seen as pushy or rude. Your mastery includes the ability to use いずれ in rhetorical questions or as a way to gracefully defer a difficult decision. You recognize its role in maintaining 'wa' (harmony) by providing a certain but flexible future outlook.

For C2 learners, いずれ (Izure) is a tool for precision and stylistic flair. You can analyze its use in classical literature (where it was 'idure') and see how that history informs its modern nuances. You might use it in a speech to evoke a sense of grand scale or historical inevitability. You are fully aware of the contrast between いずれ and its synonyms like 'yagate' or 'tsui ni,' and you choose between them with absolute precision to achieve a specific emotional or intellectual effect. In professional or diplomatic settings, you use いずれ to manage extremely delicate timelines, where the ambiguity of 'when' is a strategic necessity. You can also appreciate and use the word in its most archaic forms in poetic or highly formal contexts, demonstrating a deep cultural and linguistic immersion that spans centuries of Japanese language evolution.

تمرین کن مثال‌ها نکات و راهنمایی‌ها

いずれ در ۳۰ ثانیه

A formal adverb meaning 'eventually' or 'sooner or later' in an unspecified future.
Implies certainty and inevitability, unlike the more dream-like word 'itsuka'.
Commonly used in business emails and formal speech to defer specific scheduling.
Can also mean 'which one' in formal contexts, though this is less common today.

The Japanese adverb いずれ (Izure) is a sophisticated temporal marker that translates most commonly to 'eventually,' 'sooner or later,' or 'in due course.' At its core, it suggests a point in the future that is currently unspecified but considered inevitable or highly likely to occur. Unlike the word 'itsuka' (someday), which often carries a dreamy or aspirational quality, いずれ carries a weight of certainty. It implies that while we do not know the exact date or time, the natural progression of events will lead to this outcome. This makes it an essential tool for discussing logical conclusions, inevitable changes, or future plans that are firmly intended but not yet scheduled.

Temporal Scope: It refers to an indefinite future, ranging from a few days to many years, depending on the context of the situation described.

真実はいずれ明らかになる。
(The truth will eventually come to light.)

In classical Japanese, いずれ (originally いづれ) functioned primarily as an interrogative pronoun meaning 'which one.' While this usage survives in modern Japanese (e.g., いずれか - one of them), the adverbial 'eventually' has become its most frequent application in daily communication. When used as 'eventually,' it often appears at the beginning of a sentence or immediately before the verb it modifies. It provides a sense of calm assurance or, in some contexts, an ominous warning of what is to come.

Nuance of Inevitability: It suggests that the outcome is a logical result of current circumstances, rather than a random occurrence or a mere wish.

彼はいずれ社長になるだろう。
(He will eventually become the president.)

Furthermore, いずれ is frequently paired with the particle 'にしても' to form 'いずれにしても' (in any case/regardless). This common phrase shifts the focus from 'when' to 'regardless of the outcome,' showing the word's versatility in logical structuring. In academic and business writing, this word is preferred over more colloquial expressions to maintain a professional and objective tone. It allows the speaker to acknowledge future possibilities without committing to a specific timeline that might be proven wrong later.

Formal Usage: In formal letters, 'いずれまた' is a standard way to say 'until next time' or 'we shall meet again eventually.'

Using いずれ correctly requires an understanding of its grammatical placement and its relationship with other time-related adverbs. Grammatically, it is an adverb that usually sits before the verb or at the very start of a clause. It does not require specific particles like 'ni' or 'de' when used to mean 'eventually.' However, its meaning can change significantly when combined with other words, such as 'いずれも' (both/all) or 'いずれか' (either/one of). For B1 learners, the focus should remain on its adverbial use to describe future events.

Sentence Placement: Usually placed at the beginning of the sentence to set the temporal frame, or right before the predicate for emphasis.

いずれお会いできるのを楽しみにしています。
(I look forward to meeting you eventually.)

One of the most powerful ways to use いずれ is in the construction いずれにしても. This phrase is used to summarize a discussion or to state that regardless of which path is taken, the result will be the same. It is a staple of business Japanese and debate. For example, if you are discussing two different marketing strategies, you might say, 'いずれにしても、予算が足りない' (In any case, the budget is insufficient). This demonstrates a high level of linguistic maturity by showing you can synthesize complex information into a single logical conclusion.

Common Pairings: Often paired with 'だろう' (probably) or 'ことになる' (it will be decided that) to express a logical future outcome.

この問題はいずれ解決するでしょう。
(This problem will eventually be solved.)

In terms of register, いずれ is quite versatile but leans toward formal or polite speech. In very casual conversation with close friends, people might prefer 'itsuka' or 'sono uchi.' However, using いずれ in a casual setting isn't 'wrong'; it just adds a touch of seriousness or intellectual weight to your statement. For instance, telling a friend 'いずれわかるよ' (You'll find out eventually) sounds more mysterious and certain than 'itsuka wakaru yo.' It suggests that the knowledge is inevitable, not just a possibility.

The 'Which' Function: Remember that 'いずれか' means 'one of' or 'either.' Do not confuse this with the adverbial 'eventually.'

You will encounter いずれ in a wide variety of contexts, ranging from high-stakes business negotiations to the dramatic dialogue of anime and literature. In a professional setting, it is the go-to word for acknowledging a future task or meeting that hasn't been scheduled yet. For example, a manager might say, 'いずれ詳しく説明します' (I will explain in detail eventually). This allows them to defer the explanation while assuring the listener that it will definitely happen. It is also common in news reports when discussing long-term trends or inevitable economic shifts.

Business Context: Used to manage expectations about future events without committing to a specific deadline.

その件については、いずれ改めてご連絡します。
(Regarding that matter, I will contact you again eventually.)

In the world of fiction, particularly in mystery or fantasy genres, いずれ is often used by characters who possess secret knowledge or who are making prophecies. A villain might say, 'いずれお前も気づくだろう' (Eventually, you too will realize), which sounds far more certain and menacing than using 'itsuka.' This usage highlights the word's inherent sense of inevitability. It suggests that the future is already written, and the characters are simply waiting for time to catch up. This 'prophetic' nuance is a key reason why it appears so often in dramatic storytelling.

News & Media: Commonly used in weather forecasts or economic predictions: 'いずれ雨になるでしょう' (It will eventually rain).

この技術はいずれ世界を変えるだろう。
(This technology will eventually change the world.)

Finally, you will hear it in everyday polite conversation, especially when saying goodbye. The phrase 'いずれまた' is a common, slightly formal way to say 'see you later' or 'let's meet again sometime.' It implies a genuine intention to meet again, even if there are no current plans. This makes it a warmer and more committed alternative to the standard 'sayonara.' By using いずれ, the speaker acknowledges the flow of time and expresses confidence that their paths will cross again in the future.

Daily Life: Used when discussing life stages, such as marriage, moving, or career changes that are expected but not immediate.

One of the most frequent mistakes learners make is confusing いずれ with いつか (itsuka). While both can be translated as 'someday' or 'eventually,' they are not interchangeable. 'Itsuka' is often used for dreams, wishes, or possibilities that might not actually happen (e.g., 'Someday I want to go to Mars'). In contrast, いずれ implies that the event is a certainty or a logical outcome. Using いずれ for a wild, unrealistic dream can sound strange or overly confident, as if you are stating that your trip to Mars is an inevitable fact of life.

Mistake 1: Dream vs. Certainty: Don't use 'いずれ' for purely aspirational goals. Use 'itsuka' for 'I hope to...' and 'いずれ' for 'It will happen.'

❌ いずれ宝くじに当たりたい。
✅ いつか宝くじに当たりたい。
(I want to win the lottery someday.)

Another common error is confusing the adverbial 'eventually' with the pronoun 'which.' As mentioned before, いずれ can mean 'which of the two' or 'which of many' in formal contexts. Learners sometimes try to use it as a simple 'which' (dore/dochira) in casual conversation, which sounds jarringly archaic or overly stiff. For example, asking a friend 'いずれが好き？' (Which do you like?) sounds like you are a character from a 19th-century novel. Stick to 'dochira' or 'dore' for simple choices and save いずれ for formal writing or specific set phrases like 'いずれか.'

Mistake 2: Confusing with 'Yagate': 'Yagate' implies a shorter timeframe ('before long'), while 'いずれ' can span a much longer, more indefinite period.

❌ 彼はいずれ来ます (when he is 5 minutes late).
✅ 彼はまもなく来ます。
(He will arrive shortly.)

Finally, be careful with the phrase いずれにしても. While it is a great phrase, some learners use it to mean 'anyway' in the sense of 'changing the subject.' In Japanese, 'tonikaku' is better for abruptly changing the topic. いずれにしても is more about concluding or synthesizing the previous points. If you use it to jump to a completely unrelated topic, it can make the conversation feel disjointed. Use it when you want to say, 'Regardless of all these factors we just discussed, the bottom line is...'

Mistake 3: Overuse in Casual Speech: Using 'いずれ' too much in very casual settings can make you sound slightly detached or overly formal. 'Sono uchi' is a more natural casual alternative.

To master いずれ, it is helpful to compare it with other Japanese words that deal with the concept of 'eventually' or 'someday.' Each of these words has a specific nuance that dictates when it should be used. The most common comparison is with いつか (itsuka), やがて (yagate), and そのうち (sono uchi). Understanding these differences will help you sound more like a native speaker and ensure your intentions are clearly understood.

いずれ vs. いつか: 'いずれ' implies certainty and inevitability. 'いつか' is more about possibility, dreams, and unspecified points in time that may never come.

いつか世界一周したい。
(I want to travel around the world someday - a dream.)
いずれ世界一周するつもりだ。
(I intend to travel around the world eventually - a plan.)

やがて (yagate) is another close synonym, but it focuses on the passage of time and the transition from one state to another. It often translates to 'before long' or 'soon after.' While いずれ looks forward to a distant, unspecified point, やがて suggests that the change is already beginning or will happen relatively quickly. For example, 'やがて夜が明けた' (Before long, dawn broke). It is more descriptive of a process, whereas いずれ is more about the finality of the outcome.

いずれ vs. そのうち: 'そのうち' is the casual, everyday version of 'いずれ.' It is used for things that will happen 'one of these days' or 'soonish.'

そのうち遊びに行くよ。
(I'll come visit you one of these days - casual.)

Finally, consider 最終的に (saishuteki ni), which means 'finally' or 'ultimately.' This word emphasizes the end of a long process or a series of events. While いずれ points to a future time, 最終的に points to the result of an effort. If you say 'いずれ成功する,' you are focusing on the fact that success will come. If you say '最終的に成功した,' you are focusing on the fact that after many struggles, you finally succeeded. いずれ is prospective (looking forward), while 最終的に is often retrospective (looking back) or focused on the final step of a plan.

Comparison Table

Word	Nuance	Formality
いずれ	Inevitable/Certain	Formal/Polite
いつか	Dream/Possibility	Neutral
そのうち	Soon/One of these days	Casual
やがて	Before long/Process	Literary

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سطح دشواری

گرامر لازم

مثال‌ها بر اساس سطح

いずれまた会いましょう。

Let's meet again eventually.

いずれ is used here as a polite way to say 'sometime in the future.'

いずれわかります。

You will understand eventually.

Simple future certainty.

いずれ日本に行きたいです。

I want to go to Japan eventually.

Slightly more formal than 'itsuka'.

いずれ、雨が降ります。

Eventually, it will rain.

Predicting a natural event.

いずれ、彼は来ます。

He will come eventually.

Expressing certainty about someone's arrival.

いずれ、この本を読みます。

I will read this book eventually.

Indicating a future intention.

いずれ、わかりますよ。

You'll see eventually.

Adding 'yo' for emphasis.

いずれ、またね！

See you eventually!

Very casual use of a formal word.

いずれ、その仕事は終わります。

Eventually, that work will finish.

Focusing on the inevitable end of a task.

いずれにしても、行きましょう。

In any case, let's go.

Introduction of 'いずれにしても'.

いずれ、新しい家を買いたいです。

Eventually, I want to buy a new house.

Expressing a long-term goal.

いずれ、本当のことを話します。

I will tell the truth eventually.

Promising a future action.

いずれ、春が来ます。

Eventually, spring will come.

Describing a natural cycle.

いずれ、彼も大人になります。

Eventually, he too will become an adult.

Discussing growth and time.

いずれ、この町も変わるでしょう。

Eventually, this town will change too.

Making a prediction about the environment.

いずれ、答えが見つかります。

Eventually, the answer will be found.

Expressing optimism about a problem.

いずれ詳しくご説明いたします。

I will explain in detail eventually.

Formal humble language (keigo) with いずれ.

いずれにしても、準備が必要です。

In any case, preparation is necessary.

Using いずれにしても to state a logical requirement.

いずれ、この努力は報われるはずだ。

Eventually, this effort should pay off.

Expressing logical expectation with 'hazuda'.

いずれ、彼がリーダーになるだろう。

Eventually, he will probably become the leader.

Predicting a career path.

いずれ、その問題に直面することになる。

Eventually, we will end up facing that problem.

Using 'koto ni naru' for inevitable outcomes.

いずれ、またお会いできる日を楽しみにしています。

I look forward to the day we can meet again eventually.

Standard formal closing for letters/emails.

いずれ、真実が明らかになる時が来る。

Eventually, the time will come when the truth is revealed.

Dramatic use of いずれ.

いずれ、自分の店を持ちたいと思っています。

I'm thinking that eventually, I want to have my own shop.

Expressing a firm future intention.

いずれにしても、結果を待つしかありません。

In any case, we have no choice but to wait for the results.

Using 'shika arimasen' to show limited options.

いずれ、科学がこの謎を解明するだろう。

Eventually, science will probably solve this mystery.

Predicting scientific progress.

いずれ、社会の仕組みも変わらざるを得ない。

Eventually, the structure of society will have no choice but to change.

Using 'zaru o enai' for unavoidable change.

いずれ、彼女の才能が認められる日が来るに違いない。

The day will surely come when her talent is recognized eventually.

Using 'ni chigai nai' for strong conviction.

いずれ、この土地も再開発される予定です。

Eventually, this land is scheduled to be redeveloped.

Discussing official plans.

いずれ、我々は決断を迫られることになるだろう。

Eventually, we will probably be forced to make a decision.

Using passive voice 'semarareru'.

いずれ、人工知能が人間を追い越すという議論がある。

There is an argument that eventually, AI will overtake humans.

Discussing complex theories.

いずれ、この伝統も途絶えてしまうかもしれない。

Eventually, this tradition might end up dying out.

Using 'teshimau kamoshirenai' for negative possibilities.

いずれにせよ、事態は予断を許さない状況にある。

In any case, the situation remains unpredictable.

Using 'yodan o yurusanai' (unpredictable) with いずれにせよ.

いずれ、歴史が彼を正当に評価するであろう。

Eventually, history will likely judge him fairly.

Formal literary style with 'dearou'.

いずれ、この矛盾が破綻を招くことは明白だ。

It is clear that eventually, this contradiction will lead to a collapse.

Using 'meihaku' (obvious) for logical conclusions.

いずれ、万物は流転し、形を変えていく。

Eventually, all things flow and change their form.

Philosophical usage (pantha rhei).

いずれ、彼らの野望は潰える運命にあった。

Eventually, their ambitions were destined to crumble.

Using 'unmei ni atta' for past destiny.

いずれ、経済のグローバル化は避けられない潮流となる。

Eventually, economic globalization will become an inevitable trend.

Using 'chouryuu' (trend/tide).

いずれ、言葉の壁は技術によって取り払われるだろう。

Eventually, language barriers will be removed by technology.

Predicting technological shifts.

いずれ、宇宙の起源が解明される時が来るのかもしれない。

Perhaps the time will come when the origin of the universe is elucidated eventually.

Complex speculative sentence.

いずれ、諸行無常の響きの中に、全ては消え去る。

Eventually, everything vanishes within the sound of impermanence.

Highly literary, referencing Buddhist concepts.

いずれ、法廷がこの不当な判決を覆すことを切に願う。

I earnestly hope that eventually, the court will overturn this unjust ruling.

Formal legal/political context.

いずれ、文明の利器が自然を凌駕する日は来ないだろう。

The day will likely never come when the tools of civilization surpass nature eventually.

Complex negative prediction.

いずれ、国家という枠組み自体が形骸化していく可能性がある。

There is a possibility that eventually, the framework of the nation-state itself will become a mere shell.

Using 'keigaika' (becoming a shell/formalized).

いずれ、真理を追究する道は険しくとも、歩みを止めてはならない。

Even if the path to seeking truth is eventually steep, one must not stop walking.

Moral/philosophical exhortation.

いずれ、生命の神秘が解き明かされる日は、人類の黄昏となるのか。

Will the day the mystery of life is eventually unraveled be the twilight of humanity?

Rhetorical/existential question.

いずれ、この静寂が嵐の前触れであったことを知ることになる。

Eventually, we will come to know that this silence was the precursor to a storm.

Foreshadowing in high literature.

いずれ、情報の氾濫が個人の思考を奪う事態を危惧している。

I fear a situation where eventually, the flood of information robs individuals of their thoughts.

Expressing deep concern (kigu).

ترکیب‌های رایج

いずれわかる

いずれ明らかになる

いずれ解決する

いずれお会いする

いずれにしても

いずれか一つ

いずれも同様

いずれ来る

いずれまた

いずれ詳しく

عبارات رایج

いずれにしても (In any case)

いずれまた (See you again eventually)

いずれわかるよ (You'll find out eventually)

いずれかを選択する (Choose one of them)

いずれも正しい (Both/All are correct)

いずれにせよ (Regardless/Anyway)

いずれ劣らぬ (Both equally good)

いずれ菖蒲か杜若 (Both are so beautiful it's hard to choose)

いずれそのうちに (One of these days soon)

いずれのご来場を (Looking forward to your visit eventually)

اغلب اشتباه گرفته می‌شود با

いずれ vs いつか

Itsuka is for dreams/possibilities; Izure is for certainties/inevitabilities.

いずれ vs やがて

Yagate is 'before long' (sooner); Izure is 'eventually' (could be much later).

いずれ vs そのうち

Sono uchi is casual; Izure is formal/polite.

اصطلاحات و عبارات

به‌راحتی اشتباه گرفته می‌شود

いずれ vs

الگوهای جمله‌سازی

نحوه استفاده

nuance

It implies a logical flow of time leading to a result.

formality

Higher than 'sono uchi', similar to 'yagate' but less literary.

اشتباهات رایج

Using 'いずれ' for a specific, known time.
Using 'いずれ' for unrealistic dreams (use 'itsuka' instead).
Confusing 'いずれか' (one of) with 'いずれ' (eventually).
Adding 'ni' after 'いずれ' when meaning 'eventually'.
Using 'いずれ' in very casual slang-heavy conversations.

نکات

Business Writing

Use 'いずれ' to acknowledge a request you can't fulfill immediately but intend to do later.

Certainty

Use 'いずれ' when you are 90% sure something will happen, even if you don't know when.

Logical Flow

Use 'いずれにしても' to transition from a list of possibilities to a single conclusion.

Softening

Use 'いずれ' to make a future promise sound less like a rigid deadline and more like a natural intent.

Synonym Choice

Choose 'いずれ' over 'itsuka' if you want to sound more professional and mature.

Context Clues

If you see 'いずれ' at the start of a sentence followed by a comma, it almost always means 'eventually'.

Pitch Accent

Keep your pitch flat (heiban) to avoid sounding like you are asking a question.

Politeness

Remember that 'いずれまた' is a very safe and polite way to end a conversation with a superior.

Email Closings

Pair 'いずれ' with 'tanoshimi ni shiteimasu' (looking forward to) for a warm but professional closing.

Avoid 'Itsuka' for Facts

Don't say 'Itsuka the sun will rise.' Use 'Izure' or just the plain verb, as it's a fact, not a dream.

حفظ کنید

ریشه کلمه

Derived from the classical Japanese 'idure,' which was primarily an interrogative pronoun for 'which.'

بافت فرهنگی

It helps avoid direct conflict by deferring difficult topics to an unspecified future.

Use 'いずれ' in follow-up emails to maintain a connection without being pushy.

تمرین در زندگی واقعی

موقعیت‌های واقعی

شروع‌کننده‌های مکالمه

"いずれ日本に住みたいと思っていますか？ (Do you want to live in Japan eventually?)"

"いずれこの問題はどうなると思いますか？ (What do you think will happen to this problem eventually?)"

"いずれまた会えるといいですね。 (It would be nice if we could meet again eventually, wouldn't it?)"

"いずれにしても、今日は楽しかったですね。 (In any case, today was fun, wasn't it?)"

"いずれ自分の会社を作りたいですか？ (Do you want to start your own company eventually?)"

موضوعات نگارش

いずれ達成したい目標について書いてください。 (Write about a goal you want to achieve eventually.)

いずれ解決しなければならない問題は何ですか？ (What is a problem that must be solved eventually?)

いずれにしても変えられない事実は何ですか？ (What is a fact that cannot be changed in any case?)

いずれまた行きたい場所はどこですか？ (Where is a place you want to go again eventually?)

いずれ自分の人生はどうなっていると思いますか？ (How do you think your life will be eventually?)

سوالات متداول

10 سوال

No, 'いずれ' is strictly used for future events or logical conclusions. For the past, you would use words like 'saishuteki ni' or 'kekkyoku'.

No, 'いずれ' implies an unspecified time. If you know it's tomorrow, just use 'ashita'.

Yes, but it sounds a bit serious. 'Sono uchi' is more common with friends.

Not always. In formal contexts, it can mean 'which one' (e.g., いずれか).

They are almost identical. 'いずれにせよ' is slightly more formal and literary.

Yes, it is often used for warnings, like 'Eventually, you will regret this.'

It can function as a pronoun (noun-like), but it is most commonly used as an adverb.

It is written as 何れ, but this is rare. Hiragana is the standard.

Yes, it is a common B1/N3 level vocabulary word.

When followed by 'mo' (いずれも), it means 'both' or 'all of them'.