water ice vs ground ice

water ice and ground ice both are nouns.

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

As nouns, ground ice is a hyponym of water ice; that is, ground ice is a word with a more specific, narrower meaning than water ice:

Other hyponyms of water ice include black ice, frost, hoar, hoarfrost, rime, hailstone, icicle, segregated ice, Taber ice.

water ice (noun)	ground ice (noun)
an ice containing no milk but having a mushy consistency; usually made from fruit juice	all types of ice formed in freezing and frozen ground.
water frozen in the solid state