cellphone vs cellular telephone

cellphone and cellular telephone both are nouns.

Word	Noun	Adjective	Verb	Adverb
cellphone	Yes	No	No	No
cellular telephone	Yes	No	No	No

As nouns, cellphone and cellular telephone are synonyms defined as:

cellphone and cellular telephone: a hand-held mobile radiotelephone for use in an area divided into small sections, each with its own short-range transmitter/receiver

Other synonyms of cellphone include cell, cellular phone, mobile phone.

cellphone (noun)	cellular telephone (noun)
a hand-held mobile radiotelephone for use in an area divided into small sections, each with its own short-range transmitter/receiver	a hand-held mobile radiotelephone for use in an area divided into small sections, each with its own short-range transmitter/receiver