adverb, noun which may take the genitive case particle 'no'
a few years ago; some years back
Refers to an unspecified time several years in the past. Can be used adverbially or with の to modify a noun.
数年前にこの町に引っ越してきました。
I moved to this town a few years ago.
それは数年前の出来事です。
That is an event from a few years ago.