phone number vs signal

phone number and signal both are nouns.

Word	Noun	Adjective	Verb	Adverb
phone number	Yes	No	No	No
signal	Yes	Yes	Yes	No

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

Other hypernyms of phone number include sign, signaling, signalling.

phone number (noun)	signal (noun)
the number is used in calling a particular telephone	any nonverbal action or gesture that encodes a message
	any incitement to action
	an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes

phone number (adjective)	signal (adjective)
	notably out of the ordinary

phone number (verb)	signal (verb)
	communicate silently and non-verbally by signals or signs
	be a signal for or a symptom of