Three Books
Three Volumes
noun
Three books equals three books.
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.
この図書館では、本は三冊まで借りれます。
In this library, you can borrow up to three books.
週末に三冊全部読むのは、ちょっと無理かも。
I may not be able to read all three books in a weekend.
お前から借りたミステリー小説のうち、三冊がどこかに消えたんだよ。これこそ本当のミステリーだ。
Three of the mystery novels I borrowed from you have disappeared somewhere. Now that's a real mystery.