LATIN DICTIONARYLexicon Latīnum
suffix

-cum1

-cum (indeclinable)
Classical[ˈkũː]Ecclesiastical[ˈkum]

Meaning

  1. indeclinablemorphemewith
    mē (“me”) + -cum → mēcum (“with me”)

Origins

Postpositional variant of the preposition cum (“with”) when used with pronouns; presumably reflects the fact that Proto-Indo-European *ḱóm was an adverb and could be either pre– or postposed.

suffix · neutersecond declension
-cum2
-cum n (genitive -cī)
Classical[ˈkũː]Ecclesiastical[ˈkum]

Meaning

  1. morphemeneutersuffixed to nouns of any gender, forms neuter nouns
    cantus + -cum → canticum

Origins

Substantivisation of the neuter forms of -cus.

Quick answers

What does -cum mean in Latin?
-cum, a suffix, means “with”.
How do you pronounce -cum?
In classical Latin, [ˈkũː]; in ecclesiastical (church) Latin, [ˈkum].