ठंडा खाना

You use it just like a regular noun phrase. You can say you are eating it or that the food has become cold. It is a simple combination of the adjective thanda (cold) and the noun khana (food/to eat). Use it when the steam has stopped rising from your plate.

Use it when you arrive late to the dinner table. It is perfect for telling a waiter that your soup isn't hot. You might use it when texting a friend to hurry up before the pizza cools. It is very common in daily domestic life.

Do not use it for things meant to be cold. You would not call ice cream or a salad thanda khana. For those, you just use the adjective thanda or thandi. Avoid using it in formal business meetings unless you are actually discussing catering. It is a bit too domestic for a corporate strategy session.

Indian culture revolves around garam-garam (piping hot) food. Mothers will often wait to make rotis until you sit down to eat. Thanda khana is often associated with being overworked or neglected. Eating hot food is considered essential for good digestion and hospitality. If you serve someone thanda khana, it might be seen as a lack of care.

The most common variation is the sentence Khana thanda ho raha hai. This means "The food is getting cold." You will also hear Thanda-thanda khana, which adds a bit of emphasis. Sometimes people say Basi khana to mean stale food, which is much worse than just being cold.