Kind, sort, type, or class — used to indicate a category or group.
動物は哺乳類、爬虫類、鳥類などの類に分けられる。
Animals are divided into categories such as mammals, reptiles, and birds.
この類の問題は練習すれば解けるようになる。
Problems of this type can be solved with practice.
類を見れば性質の違いがわかる。
By looking at the category you can see differences in properties.
A similar example or parallel; used to point out something of the same kind (often in phrases like '〜の類').
彼の言ったことの類は過去にも何度か聞いた。
I've heard similar things he said several times before.
そういう類の説明では納得できない。
I can't be convinced by that kind of explanation.