isidium

noun

isid·​i·​um

īˈsidēəm

plural isidia

-ēə

: an outgrowth from the surface of the thallus in certain lichens that resembles a soredium

Word History

Etymology

New Latin, from Isidium, supposed genus of lichens, irregular from Isis genus of gorgonians + Greek eidos form; from the resemblance of lichens that have isidia to gorgonians

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!