glia vs oligodendroglia

glia and oligodendroglia both are nouns.

Word	Noun	Adjective	Verb	Adverb
glia	Yes	No	No	No
oligodendroglia	Yes	No	No	No

As nouns, oligodendroglia is a hyponym of glia; that is, oligodendroglia is a word with a more specific, narrower meaning than glia:

glia: sustentacular tissue that surrounds and supports neurons in the central nervous system; glial and neural cells together compose the tissue of the central nervous system
oligodendroglia: tissue consisting of glial cells with sheetlike processes that form the myelin sheath of nerve fibers

Other hyponyms of glia include astroglia, macroglia, microglia, oligodendria.

glia (noun)	oligodendroglia (noun)
sustentacular tissue that surrounds and supports neurons in the central nervous system; glial and neural cells together compose the tissue of the central nervous system	tissue consisting of glial cells with sheetlike processes that form the myelin sheath of nerve fibers