ponycart vs donkey cart

ponycart and donkey cart both are nouns.

Word	Noun	Adjective	Verb	Adverb
ponycart	Yes	No	No	No
donkey cart	Yes	No	No	No

As nouns, ponycart and donkey cart are synonyms defined as:

Other synonyms of ponycart include pony cart, tub-cart.

ponycart (noun)	donkey cart (noun)
a cart with an underslung axle and two seats	a cart with an underslung axle and two seats