smart phone vs cellphone

smart phone and cellphone both are nouns.

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

As nouns, cellphone is a hypernym of smart phone; that is, cellphone is a word with a broader meaning than smart phone:

smart phone: a mobile phone with more advanced computing capability and connectivity than basic feature phones
cellphone: a hand-held mobile radiotelephone for use in an area divided into small sections, each with its own short-range transmitter/receiver

Other hypernyms of smart phone include cell, cellular phone, cellular telephone, mobile phone.

smart phone (noun)	cellphone (noun)
a mobile phone with more advanced computing capability and connectivity than basic feature phones	a hand-held mobile radiotelephone for use in an area divided into small sections, each with its own short-range transmitter/receiver