1A book; a bound printed publication containing writing or pictures, read as a single volume.
週末に図書館で本を三冊借りた。
I borrowed three books from the library over the weekend.
この本は小学生向けに書かれている。
This book is written for elementary school students.
彼女は毎晩寝る前に本を読む。
She reads a book every night before bed.
好きな作家の新しい本が発売された。
A new book by my favorite author was released.
2A prefix attached to nouns meaning "this," "the present," or "the matter in question" — common in formal/written Japanese (e.g. 本日 "today," 本件 "this matter").
本日は午後３時より説明会を行います。
Today, we will hold the briefing session from 3 p.m.
本件について、担当者からご連絡いたします。
Regarding this matter, our staff will contact you.
本大会は来週の日曜日に開催されます。
This tournament will be held next Sunday.
3A prefix meaning "main," "head," or "principal," used for the central branch of an organization or the core of a topic (e.g. 本社 "head office," 本題 "main topic").
本社は大阪にあり、各地に支店がある。
The head office is in Osaka, with branches in various locations.
雑談はさておき、そろそろ本題に入りましょう。
Setting small talk aside, let's get to the main topic.
4A prefix meaning "real," "genuine," or "proper," used to distinguish something from an imitation or a trial run (e.g. 本物 "the real thing," 本番 "the actual performance").
これは本物の革でできたバッグです。
This bag is made of genuine leather.
リハーサルは終わったので、あとは本番だけだ。
The rehearsal is over, so now it's just the real performance.
5A counter (〜本) for long, thin objects (pens, bottles), for films or broadcast episodes, for goals or home runs, and for phone calls.
机の上に鉛筆が二本ある。
There are two pencils on the desk.
今夜は映画を一本見るつもりだ。
Tonight I plan to watch one movie.
彼は今シーズン、ホームランを二十本打った。
He hit twenty home runs this season.