e·rupt / iˈrəpt/ • v. [intr.] (of a volcano) become active and eject lava, ash, and gases. ∎ be ejected from an active volcano: hot lava erupted from the crust. ∎ (of an object) explode with fire and noise resembling an active volcano: smoke bombs erupted everywhere. ∎ break out or burst forth suddenly and dramatically: fierce fighting erupted between the army and guerrillas. ∎ give vent to anger, enthusiasm, amusement, or other feelings in a sudden and noisy way: the soldiers erupted in fits of laughter. ∎ (of a pimple, rash, or other prominent mark) suddenly appear on the skin. ∎ (of the skin) suddenly develop such a pimple, rash, or mark. ∎ (of a tooth) break through the gums during normal development.