- A prefix from the Latin preposition cum, signifying with,
together, in conjunction, very, etc. It is used in the form com- before
b, m, p, and sometimes f, and by assimilation becomes col- before l,
cor- before r, and con- before any consonant except b, h, l, m, p, r,
and w. Before a vowel com- becomes co-; also before h, w, and sometimes
before other consonants.