Last Year
noun
The past year is just last year.
きょねん
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
去年の四月に日本にきました。
I came to Japan in April of last year.
去年、はじめて夏コミにさんせんしました。
Last year, I participated in the Summer Comiket for the first time.
彼はハンバーガーを毎日食べるので、去年よりも太ってしまった。
He is fatter than he was last year because he eats hamburgers every day.