A shop that sells books; a bookstore or bookshop.
駅前の本屋で小説の新刊を買った。
I bought a new novel at the bookstore in front of the station.
この本屋は児童書の品揃えが豊富だ。
This bookstore has a rich selection of children's books.
本屋さんでアルバイトを始めた友達がいる。
I have a friend who started a part-time job at a bookstore.
Can sometimes mean a publisher (an older or industry usage).
その本は地元の本屋が出したものだと聞いたが、ここでは『本屋』が出版社を指すこともある。
I heard that book was published by a local 'honya' — here 'honya' can sometimes refer to the publisher.
May mean the main building or main hall in some contexts (an older or specialized usage).
社寺の本屋（本殿とは別に本館を指す古い言い方）が修理中だ。
The honya of the shrine (an old term referring to the main building, distinct from the main hall) is under repair.