1. The act of breaking or bursting forth from inclosure or confinement; a violent emission of any thing, particularly of flames and lava from a volcano. The eruptions of Hecla in 1783, were extraordinary for the quantity of lava discharged.
2. A sudden or violent rushing forth of men or troops for invasion; sudden excursion.
Incensed at such eruption bold.
3. A burst of voice; violent exclamation. [Little [used.]
4. In medical science, a breaking out of humors; a copious excretion of humors on the skin, in pustules; also, an efflorescence or redness on the skin, as in scarlatina; exanthemata; petechiae; vibices;as in small pox, measles and fevers.