LATIN DICTIONARYLexicon Latīnum
numeralfirst/second-declension numeral

ūndecimus

ūndecimus (feminine ūndecima, neuter ūndecimum)
Classical[uːnˈdɛ.kɪ.mʊs]Ecclesiastical[unˈdɛː.t͡ʃi.mus]
Mille Verba core vocabulary

Meaning

  1. numeraleleventh
    et iam stellarum sublime coegerat agmen Lucifer undecimus.and now the stars were driven away by the eleventh dawn.8 CE, Ovidius, Metamorphoses 11.97–98

In the readers how our graded readers gloss it

Declension

singular
formmasculinefeminineneuter
nominativeūndecimusūndecimaūndecimum
genitiveūndecimīūndecimaeūndecimī
dativeūndecimōūndecimaeūndecimō
accusativeūndecimumūndecimamūndecimum
ablativeūndecimōūndecimāūndecimō
vocativeūndecimeūndecimaūndecimum
plural
formmasculinefeminineneuter
nominativeūndecimīūndecimaeūndecima
genitiveūndecimōrumūndecimārumūndecimōrum
dativeūndecimīsūndecimīsūndecimīs
accusativeūndecimōsūndecimāsūndecima
ablativeūndecimīsūndecimīsūndecimīs
vocativeūndecimīūndecimaeūndecima

undĕcĭmus, a, um, num. adj. unusdecimus,
I. the eleventh: legio, Liv. 30, 18, 10: annus, Verg. E. 8, 39: dies, Plin. 11, 54, 118, § 283.

Origins

From ūndecim 'eleven'.

Quick answers

What does ūndecimus mean in Latin?
ūndecimus, a numeral, means “eleventh”.
How do you pronounce ūndecimus?
In classical Latin, [uːnˈdɛ.kɪ.mʊs]; in ecclesiastical (church) Latin, [unˈdɛː.t͡ʃi.mus].