ischemia vs TIA

ischemia and TIA both are nouns.

Word	Noun	Adjective	Verb	Adverb
ischemia	Yes	No	No	No
TIA	Yes	No	No	No

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

ischemia: local anemia in a given body part sometimes resulting from vasoconstriction or thrombosis or embolism
TIA: brief episode in which the brain gets insufficient blood supply; symptoms depend on the site of the blockage

Other hyponyms of ischemia include ischaemic stroke, ischemic stroke, transient ischemic attack.

ischemia (noun)	TIA (noun)
local anemia in a given body part sometimes resulting from vasoconstriction or thrombosis or embolism	brief episode in which the brain gets insufficient blood supply; symptoms depend on the site of the blockage