Octodecimos

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  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]