epilepsy (n.)

before vowels reduced to ep-, before aspirated vowels eph-, word-forming element meaning "on, upon, above," also "in addition to; toward, among," from Greek epi "upon, at, close upon (in space or time), on the occasion of, in addition," also "after," from PIE *epi, *opi "near, at, against" (source also of Sanskrit api "also, besides;" Avestan aipi "also, to, toward;" Armenian ev "also, and;" Latin ob "toward, against, in the way of;" Oscan op, Greek opi- "behind;" Hittite appizzis "younger;" Lithuanian ap- "about, near;" Old Church Slavonic ob "on"). A productive prefix in Greek; also used in modern scientific compounds (such as epicenter).

1560s, in mathematics, from Greek lemma (plural lemmata) "something received or taken; an argument; something taken for granted," from root of lambanein "to take," from PIE root *(s)lagw- "to seize, take" (source also of Sanskrit labhate, rabhate "seizes;" Old English læccan "to seize, grasp;" Greek lazomai "I take, grasp;" Old Church Slavonic leca "to catch, snare;" Lithuanian lobis "possession, riches"). Related: Lemmatical.