"Book" has been used to translate the Latin word "liber", which is the word used by the Ancient Romans for the parts of a bigger document, each of which would have been written on a different scroll.

Latin "liber" was used to translate the Greek words "biblion" or "byblos", which are thus the oldest source of the word "book". "Byblos" originally meant papyrus in Greek, but later it was also used for the parts of a big document. A later form of this word, which was more specialized with the meaning of "material for writing" or "book", is "biblion" (a diminutive), having the plural "ta biblia" = "the books", which is the source of English "bible".