ocean current vs current

ocean current and current both are nouns.

Word	Noun	Adjective	Verb	Adverb
ocean current	Yes	No	No	No
current	Yes	Yes	No	No

As nouns, current is a hypernym of ocean current; that is, current is a word with a broader meaning than ocean current:

ocean current: the steady flow of surface ocean water in a prevailing direction
current: a steady flow of a fluid (usually from natural causes)

Other hypernyms of ocean current include stream.

ocean current (noun)	current (noun)
the steady flow of surface ocean water in a prevailing direction	a steady flow of a fluid (usually from natural causes)
	dominant course (suggestive of running water) of successive events or ideas
	a flow of electricity through a conductor

ocean current (adjective)	current (adjective)
	occurring in or belonging to the present time