Word Study
Com-
CIDE DICTIONARY
Com-,
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. [1913 Webster]
OXFORD DICTIONARY
Com-, prefix (also co-, col-, con-, cor-) with, together, jointly, altogether.
Usage
com- is used before b, m, p, and occas. before vowels and f; co- esp. before vowels, h, and gn; col- before l, cor- before r, and con- before other consonants.
Etymology
L com-, cum with
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