twenty-fourmo Meaning, Definition & Usage

Twen`ty-four"mo adjective
Definitions
  1. Having twenty-four leaves to a sheet; as, a twenty-fourmo form, book, leaf, size, etc. -- n. A book composed of sheets, each of which is folded into twenty-four leaves; hence, indicating more or less definitely a size of book whose sheets are so folded; -- usually written 24mo, or 24°.

Webster 1913