Category:Octodecimo

Oc`todec"i*mo, a. Etym: [l. octodecim eighteen. See octavo, decimal, And -mo.]

Defn: having eighteen leaves to a sheet; as, an octodecimo form, Book, leaf, size, etc.

Octodecimo Oc`to*dec"i*mo, n.; pl. Octodecimos (.

Defn: a book composed of sheets each of which is folded into eighteen Leaves; hence; indicating more or less definitely a size of book, Whose sheets are so folded; -- usually written 18mo or 18º, and Called eighteenmo.