ecchymosis vs contusion

ecchymosis and contusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
ecchymosis	Yes	No	No	No
contusion	Yes	No	No	No

As nouns, contusion is a hypernym of ecchymosis; that is, contusion is a word with a broader meaning than ecchymosis:

ecchymosis: the purple or black-and-blue area resulting from a bruise
contusion: an injury that doesn't break the skin but results in some discoloration

Other hypernyms of ecchymosis include bruise.

ecchymosis (noun)	contusion (noun)
the escape of blood from ruptured blood vessels into the surrounding tissue to form a purple or black-and-blue spot on the skin	the action of bruising
the purple or black-and-blue area resulting from a bruise	an injury that doesn't break the skin but results in some discoloration