associate (v.)

mid-15c., "join in company, combine intimately" (transitive), from Latin associatus past participle of associare "join with," from assimilated form of ad "to" (see ad-) + sociare "unite with," from socius "companion, ally," from PIE *sokw-yo-, suffixed form of root *sekw- (1) "to follow." Related: Associated; associating. Intransitive sense of "have intercourse, be associated" is from 1640s. Earlier form of the verb was associen (late 14c.), from Old French associier "associate (with)."

1530s, "a partner in interest or business," from associate (adj.). Meaning "one admitted to a subordinate degree of membership" is from 1812.

early 15c., "allied, connected, paired; joined in an interest, object, employment or purpose," from Latin associatus, past participle of associare "join with," from assimilated form of ad "to" (see ad-) + sociare "unite with," from socius "companion, ally," from PIE *sokw-yo-, suffixed form of root *sekw- (1) "to follow."