wadi vs gully

wadi and gully both are nouns.

Word	Noun	Adjective	Verb	Adverb
wadi	Yes	No	No	No
gully	Yes	No	No	No

As nouns, gully is a hypernym of wadi; that is, gully is a word with a broader meaning than wadi:

wadi: gully or streambed in northern Africa and the Middle East that remains dry except during rainy season
gully: deep ditch cut by running water (especially after a prolonged downpour)

wadi (noun)	gully (noun)
gully or streambed in northern Africa and the Middle East that remains dry except during rainy season	deep ditch cut by running water (especially after a prolonged downpour)