gable end vs pediment

gable end and pediment both are nouns.

Word	Noun	Adjective	Verb	Adverb
gable end	Yes	No	No	No
pediment	Yes	No	No	No

As nouns, pediment is a hyponym of gable end; that is, pediment is a word with a more specific, narrower meaning than gable end:

gable end: the vertical triangular wall between the sloping ends of gable roof
pediment: a triangular gable between a horizontal entablature and a sloping roof

Other hyponyms of gable end include bell gable, corbie gable.

gable end (noun)	pediment (noun)
the vertical triangular wall between the sloping ends of gable roof	a triangular gable between a horizontal entablature and a sloping roof