smart phone vs cellular phone

smart phone and cellular phone both are nouns.

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

As nouns, cellular phone is a hypernym of smart phone; that is, cellular phone 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
cellular phone: 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, cellphone, cellular telephone, mobile phone.

smart phone (noun)	cellular phone (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