octodecimo

Definitions

1. 1.Having eighteen leaves to a sheet; as, an octodecimo form, book, leaf, size, etc.
2. 2.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.

Source: Webster's Unabridged Dictionary, 1913 edition (public domain, via GCIDE / Project Gutenberg).

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• What does "octodecimo" mean?

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Definition-first questions whose answer is octodecimo.

• What is having eighteen leaves to a sheet; as, an octodecimo form, book, leaf, size, etc called?