parsley: [14] The ultimate source of parsley is Greek petrōselínon, a compound formed from pétrā ‘rock’ (source of English petrify, petrol, etc) and sélīnon ‘parsley’ (source of English celery). From it was descended Latin petroselīnum, which in post-classical times became petrosilium. This passed into English in two distinct phases: first, direct from Latin in the Old English period as petersilie, and secondly, in the 13th century via Old French peresil as percil. By the 14th century these had started to merge together into percely, later parsley. => celery, petrol
parsley (n.)
14c. merger of Old English petersilie and Old French peresil (13c., Modern French persil), both from Medieval Latin petrosilium, from Latin petroselinum, from Greek petroselinon "rock-parsley," from petros "rock, stone" + selinon "celery" (see celery).