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.

A sudden or violent rushing forth of men or troops for invasion; sudden excursion. Incensed at such eruption bold.

A burst of voice; violent exclamation.

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.