Time
Years
noun
Years and months show the passage of time or years gone by.
歳月 is a relatively formal word that's often used in literature when reflecting on the passage of long periods of time — usually in a way that's poetic, thoughtful, or emotional.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
それから半世紀の歳月が流れ、彼のことなんてほとんど忘れかけていた時に、私達は小さなパン屋さんで偶然再会したんです。
After fifty years had passed and I was almost starting to forgot about him, we ran into each other in a tiny bakery.