eruption n.

word-forming element, in English meaning usually "out of, from," but also "upwards, completely, deprive of, without," and "former;" from Latin ex "out of, from within; from which time, since; according to; in regard to," from PIE *eghs "out" (source also of Gaulish ex-, Old Irish ess-, Old Church Slavonic izu, Russian iz). In some cases also from Greek cognate ex, ek. PIE *eghs had comparative form *eks-tero and superlative *eks-t(e)r-emo-. Often reduced to e- before -b-, -d-, -g-, consonantal -i-, -l-, -m-, -n-, -v- (as in elude, emerge, evaporate, etc.).

late 14c., in medicine, "act of bursting or breaking," in reference to a vessel, etc. of the body, from Old French rupture and directly from Latin ruptura "the breaking (of a vein), fracture (of an arm or leg)," from past-participle stem of rumpere "to break" (from PIE root *runp- "to break;" see corrupt (adj.)).

Specifically as "abdominal hernia" from early 15c. The sense of "breach of friendly relations or concord" is by 1580s; the general sense of "act or fact of breaking or bursting" is by 1640s. Rupturewort (1590s) was held to be efficacious in treating hernias, etc.

1570s, from French irruption (14c.) or directly from Latin irruptionem (nominative irruptio) "a breaking in, bursting in, invasion," noun of action from past-participle stem of irrumpere "to break in, force one's way in, burst into," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + rumpere (see rupture (n.)). Frequently confused with eruption.