conversation (n.)
mid-14c., "living together, having dealings with others," also "manner of conducting oneself in the world;" from Old French conversation, from Latin conversationem (nominative conversatio) "act of living with," noun of action from past participle stem of conversari "to live with, keep company with," literally "turn about with," from Latin com- "with" (see com-) + vertare, frequentative of vertere (see versus).

Specific sense of "talk" is 1570s. Used as a synonym for "sexual intercourse" from at least 1511, hence criminal conversation, legal term for adultery from late 18c. Related: Conversationalist; conversationist.