A shelf or case for storing books. Often used in libraries, studies, or bookstores. Slightly more formal than 本棚.
図書館の書棚にはたくさんの本が並んでいる。
Many books are lined up on the library bookshelves.
彼は書棚から一冊の小説を取り出した。
He took a novel from the bookshelf.
Compound of 書 (sho, 'book' or 'writing') and 棚 (tana, 'shelf'). The reading しょだな follows standard rendaku voicing of たな to だな.