Meaning ‘with’ or ‘together’, or sometimes an intensifier. Final sound often assimilates to match the beginning sound of the base/word to which it is attached.
con- | com- | col- | cor- | co- |
concave conceit concentrate concentric concern concert conciliate concise conclude concord concrete concur condemn condense condition conduct confect confederate confer confess confide confiscate conflate conflict conform confront confuse congest conglomerate congregate congress congruent conjecture conjunction connect connote conscript consecrate consensus consider console consonant conspire constellation constitute constrain construct consult consume contact contain continue contract contraption contrary contrast contribute convene convent convention converge converse convert convince | combat combine comfort command commence commend comment commerce commiserate commit committee commode commune commute compact company compare compartment compass compassion compatible compatriot compel compensate compete competent compile complain complement complex compliment comply compose compost compound comprehend compress comprise compunction compute | collaborate collapse collate collateral colleague collect college collide colloquium collude | correct correlate correspond corroborate corrode corrugate corrupt incorrigible | coeducation coerce coexist cohabit cohere cohort coincide cooperate coopt coordinate copilot |