food web vs food cycle

food web and food cycle both are nouns.

Word	Noun	Adjective	Verb	Adverb
food web	Yes	No	No	No
food cycle	Yes	No	No	No

As nouns, food web and food cycle are synonyms defined as:

food web and food cycle: (ecology) a community of organisms where there are several interrelated food chains

food web (noun)	food cycle (noun)
(ecology) a community of organisms where there are several interrelated food chains	(ecology) a community of organisms where there are several interrelated food chains