octodecimo

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noun

A size of a sheet of paper resulting from folding and cutting a sheet of paper into eighteenths (3.5"–4.5" x 4.9"–5.9").

Similar
18moeighteenmo18ºT
Scrabble 17
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Meanings

nounoctodecimo (plural octodecimos)

plural octodecimos

  1. papermediaA size of a sheet of paper resulting from folding and cutting a sheet of paper into eighteenths (3.5"–4.5" x 4.9"–5.9").

    Synonyms: 18mo, eighteenmo, 18º

  2. mediaA book consisting of pages of that size.

    Synonyms: 18mo, eighteenmo, 18º, T

Synonyms & antonyms

nounA size of a sheet of paper resulting from folding and cutting a sheet of paper into eighteenths (3.5"–4.5" x 4.9"–5.9").

Similar
18moeighteenmo18º

nounA book consisting of pages of that size.

Similar
18moeighteenmo18ºT
Also see
18mo

Origin

From Latin ablative of octusdecimus (“eighteenth”).

Full word history & related roots →
Cite this entry
APA

octodecimo. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/octodecimo

MLA

“octodecimo.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/octodecimo. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “octodecimo,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/octodecimo.

Source: octodecimo on Wiktionary, CC BY-SA 4.0.