epistaxis (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).

"hanging formation of carbonite of lime from the roof of a cave," 1670s, Englished from Modern Latin stalactites (used 1654 by Olaus Wormius), from Greek stalaktos "dripping, oozing out in drops," from stalassein "to trickle," from PIE root *stag- "to seep, drip, drop" (source also of German stallen, Lithuanian telžiu, telžti "to urinate") + noun suffix -ite (1). Related: Stalactic; stalactitic.