LATIN DICTIONARYLexicon Latīnum
numeralfirst/second-declension numeral with an indeclinable portion, singular only

ūnus et vīgintī

ūnus et vīgintī (feminine ūna et vīgintī, neuter ūnum et vīgintī)
Classical[ˈuː.nʊs ˈɛt wiːˈɡɪn.tiː]Ecclesiastical[ˈuː.nus ˈɛt viˈd͡ʒin.ti]

Meaning

  1. numeralsingularsingular onlytwenty-one; 21

Declension

singular
formmasculinefeminineneuter
nominativeūnus et vīgintīūna et vīgintīūnum et vīgintī
accusativeūnum et vīgintīūnam et vīgintīūnum et vīgintī
ablativeūnō et vīgintīūnā et vīgintīūnō et vīgintī
vocativeūne et vīgintīūna et vīgintīūnum et vīgintī

Origins

From ūnus (“one”) + et (“and”) + vīgintī (“twenty”).

Quick answers

What does ūnus et vīgintī mean in Latin?
ūnus et vīgintī, a numeral, means “twenty-one; 21”.
How do you pronounce ūnus et vīgintī?
In classical Latin, [ˈuː.nʊs ˈɛt wiːˈɡɪn.tiː]; in ecclesiastical (church) Latin, [ˈuː.nus ˈɛt viˈd͡ʒin.ti].