desk phone vs telephone set

desk phone and telephone set both are nouns.

Word	Noun	Adjective	Verb	Adverb
desk phone	Yes	No	No	No
telephone set	Yes	No	No	No

As nouns, telephone set is a hypernym of desk phone; that is, telephone set is a word with a broader meaning than desk phone:

desk phone: a telephone set that sits on a desk or table
telephone set: electronic equipment that converts sound into electrical signals that can be transmitted over distances and then converts received signals back into sounds

Other hypernyms of desk phone include phone, telephone.

desk phone (noun)	telephone set (noun)
a telephone set that sits on a desk or table	electronic equipment that converts sound into electrical signals that can be transmitted over distances and then converts received signals back into sounds