ponycart vs cart

ponycart and cart both are nouns.

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

As nouns, cart is a hypernym of ponycart; that is, cart is a word with a broader meaning than ponycart:

ponycart (noun)	cart (noun)
a cart with an underslung axle and two seats	a heavy open wagon usually having two wheels and drawn by an animal
	wheeled vehicle that can be pushed by a person; may have one or two or four wheels

ponycart (verb)	cart (verb)
	draw slowly or heavily
	transport something in a cart