2 entries under this word

Octodecimo

Ŏc'to-dĕs'i-mo, a.

adjective

a. [See infra.] Formed of sheets folded so as to make eighteen leaves; of, or equal to, the size of one leaf of a sheet of printing paper folded so as to make eighteen leaves; as, an octodecimo book.

Ŏc'to-dĕc'ĭ-mo, n.

noun

n.; pl. Ŏc'to-dĕc'ĭ-mōs. [Lat. octodecim, eighteen; It. ottodecimo. See supra.]

A book composed of sheets folded so as to make eighteen leaves; an octodecimo book.
The size of a book thus composed;—usually indicated thus: 18mo., 18°.