water stoma vs stoma

water stoma and stoma both are nouns.

Word	Noun	Adjective	Verb	Adverb
water stoma	Yes	No	No	No
stoma	Yes	No	No	No

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

water stoma: a pore that exudes water on the surface or margin of a leaf of higher plants
stoma: a minute epidermal pore in a leaf or stem through which gases and water vapor can pass

Other hypernyms of water stoma include pore, stomate.

water stoma (noun)	stoma (noun)
a pore that exudes water on the surface or margin of a leaf of higher plants	a mouth or mouthlike opening (especially one created by surgery on the surface of the body to create an opening to an internal organ)
	a minute epidermal pore in a leaf or stem through which gases and water vapor can pass