Last Year
noun
The past year is just last year.
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、子犬が生まれた。
Last year, a puppy was born.
去年の四月に日本にきました。
I came to Japan last April.
うちの犬は、去年から十キロ太った。
Our dog gained ten kilograms since last year.