mid-15c., assistent "one who helps or aids another," from Latin assistentem (nominative assistens), noun use of present participle of assistere "stand by, attend" (see assist (v.)). The spelling changed in French then (16c.) in English.
assistant (adj.)
mid-15c., "helpful, of assistance," from Latin assistentem (nominative assistens), present participle of assistere "stand by, attend" (see assist (v.)). The spelling changed in French then (16c.) in English.
my invaluable assistant
assimilation
assimilationist
assimilative
assist
assistance
assistant
assize
ass-kissing
associate
association
associative