Eruption

The act of breaking out or bursting forth; as: (a) A violent throwing out of flames, lava, etc., as from a volcano of a fissure in the earth's crust. (b) A sudden and overwhelming hostile movement of armed men from one country to another. Milton. (c) A violent commotion.

That which bursts forth.

A violent exclamation; ejaculation.

The breaking out of pimples, or an efflorescence, as in measles, scarlatina, etc.

symptom consisting of a breaking out and becoming visible

(of volcanoes) pouring out fumes or lava (or a deposit so formed)