ankyloglossia vs birth defect

ankyloglossia and birth defect both are nouns.

Word	Noun	Adjective	Verb	Adverb
ankyloglossia	Yes	No	No	No
birth defect	Yes	No	No	No

As nouns, birth defect is a hypernym of ankyloglossia; that is, birth defect is a word with a broader meaning than ankyloglossia:

ankyloglossia: a congenital anomaly in which the mucous membrane under the tongue is too short limiting the mobility of the tongue
birth defect: a defect that is present at birth

ankyloglossia (noun)	birth defect (noun)
a congenital anomaly in which the mucous membrane under the tongue is too short limiting the mobility of the tongue	a defect that is present at birth