1Last year, i.e. the year before the current one. Commonly used in both speech and writing. The reading 「こぞ」 is an old/literary form rarely used today.
去年、日本へ旅行しました。
I traveled to Japan last year.
去年と比べて売上が増えた。
Sales increased compared to last year.
去年の冬は例年より暖かかった。
Last winter was warmer than usual.
去年生まれた娘が、もう歩けるようになった。
My daughter, who was born last year, can already walk now.