排队

You use it just like 'to queue' in English. You can say you are currently 在排队 (in the middle of queuing). If the line is long, you might complain that there are 很多人在排队. It is a very active verb. You do not just 'stand' in a line in Chinese; you 'arrange' the line.

Use it whenever there is a sequence of people. Use it at the airport check-in counter. Use it when waiting for a table at a hotpot restaurant. Use it when boarding the bus. It is perfect for texting a friend to say you will be late. 'Sorry, I am 在排队 for coffee!'

Do not use it for digital 'queues' like a loading bar on a computer. That is usually 加载 (loading). Do not use it if you are just waiting in a room without a physical line. If you are sitting in a waiting room, use 等候 (waiting) instead. It requires a physical or metaphorical 'row' of people.

In big cities like Shanghai or Beijing, 排队 is a serious sport. Popular 'influencer' milk tea shops can have lines that last two hours. Younger generations take pride in 文明排队 (civilized queuing). It is a sign of a modern, orderly society. Sometimes you will see older folks 'cutting' the line, but the social norm is firmly pro-queue now.

You will often hear 排长队, which means a very long line. If you want to tell someone to get in line, say 请排队. If someone cuts in front of you, the word you need is 插队 (inserting into the line). That one is much less friendly!