travel vs water travel

travel and water travel both are nouns.

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

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

travel (noun)	water travel (noun)
the act of going from one place to another	travel by water
self-propelled movement
a movement through space that changes the location of something

travel (verb)	water travel (verb)
change location; move, travel, or proceed, also metaphorically
make a trip for pleasure
travel upon or across
undergo transportation as in a vehicle
undertake a journey or trip
travel from place to place, as for the purpose of finding work, preaching, or acting as a judge