Etc
In short
Etc is an abbreviation for the Latin phrase et cetera, which means 'and the rest' or 'and so on'. It is used to indicate that a list continues in a similar way without naming every item.
In plain words
Use it when you want to avoid listing every single thing in a group. It tells the reader that there are more items like the ones you already mentioned. It usually follows a list of examples.
A simple example
I need to buy fruit for the cake, such as apples, pears, bananas, etc. This shows I need more types of fruit but do not want to name them all.
Why it matters
It helps keep writing short and prevents lists from becoming too long and boring. It allows a writer to focus on the most important examples while implying a larger group.
Easy to mix up
Do not confuse it with et al., which is used specifically when referring to a list of people or authors.