What does sextusdecimus mean in Latin?

sextusdecimus, a numeral, means “sixteenth”.

How do you pronounce sextusdecimus?

In classical Latin, [sɛk.stʊsˈdɛ.kɪ.mʊs]; in ecclesiastical (church) Latin, [sek.stuzˈdɛː.t͡ʃi.mus].

Proto-Indo-European *swéḱs → Proto-Indo-European *swéḱstos → Proto-Italic *sekstos → Latin sextusdecimus.

numeralfirst/second-declension numeral with a first/second-declension numeral

sextusdecimus (feminine sextadecima, neuter sextumdecimum)

Classical[sɛk.stʊsˈdɛ.kɪ.mʊs]Ecclesiastical[sek.stuzˈdɛː.t͡ʃi.mus]

singular
form	masculine	feminine	neuter
nominative	sextusdecimus	sextadecima	sextumdecimum
genitive	sextīdecimī	sextaedecimae	sextīdecimī
dative	sextōdecimō	sextaedecimae	sextōdecimō
accusative	sextumdecimum	sextamdecimam	sextumdecimum
ablative	sextōdecimō	sextādecimā	sextōdecimō
vocative	sextedecime	sextadecima	sextumdecimum

plural
form	masculine	feminine	neuter
nominative	sextīdecimī	sextaedecimae	sextadecima
genitive	sextōrumdecimōrum	sextārumdecimārum	sextōrumdecimōrum
dative	sextīsdecimīs	sextīsdecimīs	sextīsdecimīs
accusative	sextōsdecimōs	sextāsdecimās	sextadecima
ablative	sextīsdecimīs	sextīsdecimīs	sextīsdecimīs
vocative	sextīdecimī	sextaedecimae	sextadecima

sextusdĕcĭmus, a, um, v. 1. sextus.

Proto-Italic *dekəmos Latin decimus Latin sextusdecimus From sextus (“sixth”) + decimus (“tenth”).