See Sea foam, 2. →
A variety of shale or clay slate, containing iron pyrites, the decomposition of which leads to the formation of alum, which often effloresces on the rock. →
n.
The philosophical system of Thomas Hobbes, an English materialist (1588-1679); esp., his political theory that the most perfect form of civil government is an absolute monarchy with despotic control over everything relating to law, morals, and religion. →