What does ducentēsimus mean in Latin?

ducentēsimus, a numeral, means “two hundredth”.

How do you pronounce ducentēsimus?

In classical Latin, [dʊ.kɛnˈteː.sɪ.mʊs]; in ecclesiastical (church) Latin, [du.t͡ʃenˈtɛː.s̬i.mus].

numeralfirst/second-declension numeral

ducentēsimus (feminine ducentēsima, neuter ducentēsimum)

Classical[dʊ.kɛnˈteː.sɪ.mʊs]Ecclesiastical[du.t͡ʃenˈtɛː.s̬i.mus]

singular
form	masculine	feminine	neuter
nominative	ducentēsimus	ducentēsima	ducentēsimum
genitive	ducentēsimī	ducentēsimae	ducentēsimī
dative	ducentēsimō	ducentēsimae	ducentēsimō
accusative	ducentēsimum	ducentēsimam	ducentēsimum
ablative	ducentēsimō	ducentēsimā	ducentēsimō
vocative	ducentēsime	ducentēsima	ducentēsimum

plural
form	masculine	feminine	neuter
nominative	ducentēsimī	ducentēsimae	ducentēsima
genitive	ducentēsimōrum	ducentēsimārum	ducentēsimōrum
dative	ducentēsimīs	ducentēsimīs	ducentēsimīs
accusative	ducentēsimōs	ducentēsimās	ducentēsima
ablative	ducentēsimīs	ducentēsimīs	ducentēsimīs
vocative	ducentēsimī	ducentēsimae	ducentēsima

Charlton Lewis's shorter dictionary for students: the same scholarship in plain, modern definitions.

ducentēsimus adj.

ducenti, the two hundredth : lapis, Ta.: annus, Ta.—As subst f . (sc. pars), one two hundredth, a half per cent . (as a tax), Ta.

From ducentī (“two hundred”) + -ēsimus (“-th”).