WAN vs wide area network

WAN and wide area network both are nouns.

Word	Noun	Adjective	Verb	Adverb
WAN	Yes	No	No	No
wide area network	Yes	No	No	No

As nouns, WAN and wide area network are synonyms defined as:

WAN and wide area network: a computer network that spans a wider area than does a local area network

WAN (noun)	wide area network (noun)
a computer network that spans a wider area than does a local area network	a computer network that spans a wider area than does a local area network