Octodecimo


Octodecimo
Octodecimo Oc`to*dec"i*mo, n.; pl. {Octodecimos}. 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 18[deg], and called {eighteenmo}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.