βίβλος, -ου, ἡ (variant form of βύβλος, the Egyptian papyrus, paper made from its fibrous coat),

[in LXX for סֶפֶר, the form βύβ- being sometimes used ;]

a book, a roll, used much less frequently than βιβλίον, and with a "connotation of sacredness and veneration" (MM, Exp. x), Mat.1:1 Mrk.12:26, Luk.3:4 20:42 Act.1:20 7:42 19:19; β. τ. ζωῆς, Php.4:3, Rev.3:5 20:15.†

(AS)

a book; a roll