black ice vs water ice

black ice and water ice both are nouns.

Word	Noun	Adjective	Verb	Adverb
black ice	Yes	No	No	No
water ice	Yes	No	No	No

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

black ice: a thin coating of ice (as from freezing mist) on a road or sidewalk; nearly invisible but very hazardous
water ice: water frozen in the solid state

Other hypernyms of black ice include ice.

black ice (noun)	water ice (noun)
a thin coating of ice (as from freezing mist) on a road or sidewalk; nearly invisible but very hazardous	an ice containing no milk but having a mushy consistency; usually made from fruit juice
	water frozen in the solid state