You write etc. after a list to mean there are more things of the same kind, and you are not going to name them all. It is short for Latin et cetera, 'and the rest of the things.' It lives mainly in writing. When we talk, we often say 'and so on' instead. Use it when the rest is easy to guess: apples, oranges, bananas, etc. Do not use it when the missing things matter and the reader cannot guess them. In English it is usually for things, not for people; for people in a short academic list, writers often use et al. American English almost always keeps the period: etc. Some British writing drops it. Teachers get tired of it when a student hides behind etc. instead of finishing a thought — the word is handy, not a way to stop thinking. Older books also used &c. for the same thing.