coast vs littoral zone

coast and littoral zone both are nouns.

Word	Noun	Adjective	Verb	Adverb
coast	Yes	No	Yes	No
littoral zone	Yes	No	No	No

As nouns, littoral zone is a hyponym of coast; that is, littoral zone is a word with a more specific, narrower meaning than coast:

Other hyponyms of coast include litoral, littoral, sands, landfall, seaboard, seaside, tideland.

coast (noun)	littoral zone (noun)
the act of moving smoothly along a surface while remaining in contact with it	the region of the shore of a lake or sea or ocean
the area within view
the shore of a sea or ocean
a slope down which sleds may coast

coast (verb)	littoral zone (verb)
move effortlessly; by force of gravity