kilometres per hour vs km/h

kilometres per hour and km/h both are nouns.

Word	Noun	Adjective	Verb	Adverb
kilometres per hour	Yes	No	No	No
km/h	Yes	No	No	No

As nouns, kilometres per hour and km/h are synonyms defined as:

kilometres per hour and km/h: the ratio of the distance traveled (in kilometers) to the time spent traveling (in hours)

Other synonyms of kilometres per hour include kilometers per hour, kph.

kilometres per hour (noun)	km/h (noun)
the ratio of the distance traveled (in kilometers) to the time spent traveling (in hours)	the ratio of the distance traveled (in kilometers) to the time spent traveling (in hours)