early 14c., "an attack of fever," from Old French acces "onslaught, attack; onset (of an illness)" (14c.), from Latin accessus "a coming to, an approach; way of approach, entrance," noun use of past participle of accedere "to approach," from assimilated form of ad "to" (see ad-) + cedere "go, move, withdraw" (from PIE root *ked- "to go, yield"). English sense of "an entrance" (c. 1600) is directly from Latin. Meaning "habit or power of getting into the presence of (someone or something)" is from late 14c.
