watering cart vs water cart

watering cart and water cart both are nouns.

Word	Noun	Adjective	Verb	Adverb
watering cart	Yes	No	No	No
water cart	Yes	No	No	No

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

watering cart: water cart with a tank and sprinkler for sprinkling roads
water cart: cart with a tank for water (especially with fresh water for sale)

watering cart (noun)	water cart (noun)
water cart with a tank and sprinkler for sprinkling roads	cart with a tank for water (especially with fresh water for sale)