cellphone vs mobile phone

cellphone and mobile phone both are nouns.

Word	Noun	Adjective	Verb	Adverb
cellphone	Yes	No	No	No
mobile phone	Yes	No	No	No

As nouns, cellphone and mobile phone are synonyms defined as:

cellphone and mobile phone: 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, cellular telephone.

cellphone (noun)	mobile phone (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