embolus n.

word-forming element meaning "near, at, in, on, within," from Greek en "in," cognate with Latin in (from PIE root *en "in"), and thus with en- (1). Typically assimilated to em- before -p-, -b-, -m-, -l-, and -r-.

*gwelə-, also *gwel-, Proto-Indo-European root meaning "to throw, reach," with extended sense "to pierce."

It forms all or part of: anabolic; arbalest; astrobleme; ball (n.2) "dancing party;" ballad; ballet; ballista; ballistic; ballistics; belemnite; catabolism; devil; diabolical; discobolus; emblem; embolism; hyperbola; hyperbole; kill (v.); metabolism; palaver; parable; parabola; parley; parliament; parlor; parol; parole; problem; quell; quail (v.) "lose heart, shrink, cower;" symbol.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit apa-gurya "swinging," balbaliti "whirls, twirls;" Greek ballein "to throw, to throw so as to hit," also in a looser sense, "to put, place, lay," bole "a throw, beam, ray," belemnon "dart, javelin," belone "needle," ballizein "to dance;" Armenian kelem "I torture;" Old Church Slavonic zali "pain;" Lithuanian galas "end," gėla "agony," gelti "to sting."