-cum

• (Classical Latin) IPA^(key): /kum/, [kʊ̃ˑ]
• (modern Italianate Ecclesiastical) IPA^(key): /kum/, [kum]

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.

-cum (indeclinable)

1. with

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

Substantivisation of the neuter forms of -cus.

-cum n (genitive -cī); second declension

1. suffixed to nouns of any gender, forms neuter nouns

   cantus + -cum → canticum

Second-declension noun (neuter).

• “-cum” on page 470/1 of the Oxford Latin Dictionary (1st ed., 1968–82)

Declined forms of -cus.

-cum

1. inflection of -cus:
   1. nominative/accusative/vocative neuter singular
   2. accusative masculine singular