I found an anki deck with 1000 most common words (I have to translate them to english on my own) but I couldn't find much information about the meaning of this one. One resource mentioned it means "year", is that true? Are there other meanings?
To add a bit more, this is the same word as 연대 (年代), just pronounced differently because of 두음 법칙 (the initial sound rule). Basically, hanja that are normally pronounced with ㄴ or ㄹ as the initial sound are pronounced (and spelled) differently when the hanja comes at the beginning of a word, as opposed to the middle of a compound. This is why "year" is sometimes pronounced 년 (as in 내년 (來年), "next year"), and sometimes pronounced 연 (as in 연말 (年末), "the end of the year," or 연세 (年歲), the formal word for "age").
In this case, the decade number is being treated as part of a compound word, so it is pronounced 년대 (80년대), while when used on its own, to mean an unspecified era, it would be 연대.