v.intr.
1. break out suddenly or dramatically.
2 (of a volcano) become active and eject lava etc.
3 a (of a rash, boil, etc.) appear on the skin. b (of the skin) produce a rash etc.
4 (of the teeth) break through the gums in normal development.
Derivatives:
eruption n. eruptive adj.
Etymology: L erumpere erupt- (as E-, rumpere break)