isidium

[ ahy-sid-ee-uhm ]

noun

, Botany.

, plural i·sid·i·a [ahy-, sid, -ee-, uh].

1. a coralloid outgrowth from the thallus in certain lichens.

Word History and Origins

Origin of isidium¹

1865–70; < New Latin, derivative of Isid- (stem of Isis ) Isis (from the hornlike appearance of the growth); -ium