The word book comes from Old English "bōc" which comes from Germanic root "*bōk-", cognate to beech. Similarly, in Slavic languages (e.g. Russian and Bulgarian "буква" (bukva)—"letter") is cognate to "beech". It is thus conjectured that the earliest Indo-European writings may have been carved on beech wood. Similarly, the Latin word codex, meaning a book in the modern sense (bound and with separate leaves), originally meant "block of wood."

Blook, a recent neologism, is either an object manufactured to imitate a bound book, such as an on-line book published via a blog, or a printed book that contains or is based on content from a blog.

Basic Object-Oriented Knowledge Systems is a backronym for books.