【確定】 と 【決定】 と 【決める】 はどう違いますか？ | HiNative "確定" is a noun and it means "conformation" It's formal i e 商品の確定 product confirmation "決定" is a noun and it means "decision" i e 会社の決定 a decision made by a company "決める" is a verb and it means "to decide" or "to make a decision" 進路を決める to decide one's career