Lewis & Short

4. lĭber, bri, m. [Gr. λέπειν, to peel; λέπος, λεπίς; cf. λοβός], the inner bark or rind of a tree.

  1. I. Lit.
    1. A. In gen.: obducuntur libro aut cortice trunci, Cic. N. D. 2, 47, 120: colligatae libris (arundines), Varr. R. R. 1, 8, 4: udoque docent (germen) inolescere libro, Verg. G. 2, 77: natam libro et silvestri subere clausam, id. A. 11, 554; id. E. 10, 67: quam denso fascia libro, Juv. 6, 263.
    2. B. Esp., because the ancients used the bark or rind of trees to write upon; usually the thin rind of the Egyptian papyrus, on which the books of the Greeks and Romans were usually written (v. Dict. of Antiq. p. 587 sq.): antea non fuisse chartarum usum. In palmarum foliis primo scriptitatum, dein quarundam arborum libris, Plin. 13, 11, 21, § 69.
      Hence,
  2. II. Transf.
    1. A. Paper, parchment, or rolls of any substance used to write upon (cf.: charta, membrana): quasi quom in libro scribuntur calamo litterae, Plaut. Ps. 1, 5, 131.
    2. B. Most freq. a book, work, treatise: Demetrii liber de concordia, Cic. Att. 8, 12, 6: quas (sententias) hoc libro exposui, id. Lael. 1, 3; cf. id. ib. 1, 5: dixi in eo libro, quem de rebus rusticis scripsi, id. de Sen. 15, 54: libros pervolutare, id. Att. 5, 12, 2: evolvere, id. Tusc. 1, 11, 24: volvere, id. Brut. 87, 298: legere, id. Fam. 6, 6, 8: edere, id. Fat. 1, 1: libri confectio, id. de Sen. 1, 1: tempus ad libros vacuum, id. Rep. 1, 9, 14: cujus (Platonis) in libris, id. ib. 1, 10, 16: in Graecorum libris, id. ib. 2, 11, 21: librum, si malus est, nequeo laudare, Juv. 3, 41: actorum libri, the official gazette, id. 9, 84; cf. 2, 136; and v. Dict. Antiq. s. v. Acta.
    3. C. In partic.
      1. 1. A division of a work a look: tres libri perfecti sunt de Natura Deorum, Cic. Div. 2, 1, 3: hi tres libri (de Officiis), id. Off. 3, 33, 121: sermo in novem libros distributus, id. Q. Fr. 3, 5, 1: dictum est in libro superiore, id. Off. 2, 13, 43 sicut superiore libro continetur, Quint. 11, 1, 1: versus de libro Ennii annali sexto, id. 6, 3, 86: liber primus, secundus, tertius, etc., id. 8, 1, 2; 10, 2, 20; 11, 1, 4 al.
        Sometimes, in this latter case, liber is omitted: in T. Livii primo, Quint. 9, 2, 37: in tertio de Oratore, id. 9, 1, 26: legi tuum nuper quartum de Finibus, Cic. Tusc. 5, 11, 32.
      2. 2. In relig. or pub. law lang., a religious book, scriptures; a statute-book, code: decemviris adire libros jussis, i. e. the Sibylline books, Liv. 34, 55; 21, 62; 25, 12: se cum legeret libros, recordatum esse, etc., Cic. N. D. 2, 4, 11: ut in libris est Etruscorum, id. Div. 2, 23, 50; id. Att. 9, 9, 3: caerimoniarum, rituals, Tac. A. 3, 38.
    4. D. A list, catalogue, register, Cic. Verr. 2, 3, 71, § 167.
    5. E. A letter, epistle, Nep. Lys. 4, 2; Plin. Ep. 2, 1, 5.
  3. F. A rescript, decree (post-Aug.): liber principis severus et tamen moderatus, Plin. Ep. 5, 14, 8.