If someone or something remains in a particular state or condition, they stay in that state or condition and do not change.

If you remain in a place, you stay there and do not move away.

You can say that something remains when it still exists.

If something remains to be done, it has not yet been done and still needs to be done.

The remains of something are the parts of it that are left after most of it has been taken away or destroyed.

The remains of a person or animal are the parts of their body that are left after they have died, sometimes after they have been dead for a long time.

Historical remains are things that have been found from an earlier period of history, usually buried in the ground, for example parts of buildings and pieces of pottery.

You can use remain in expressions such as the fact remains that or the question remains whether to introduce and emphasize something that you want to talk about.

If you say that it remains to be seen whether something will happen, you mean that nobody knows whether it will happen.