ski vs travel

ski and travel both are nouns.

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

As verbs, travel is a hypernym of ski; that is, travel is a word with a broader meaning than ski:

Other hypernyms of ski include go, locomote, move.

ski (noun)	travel (noun)
narrow wood or metal or plastic runners used in pairs for gliding over snow	the act of going from one place to another
	self-propelled movement
	a movement through space that changes the location of something

ski (verb)	travel (verb)
move along on skis	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