electronic signal vs signal

electronic signal and signal both are nouns.

Word	Noun	Adjective	Verb	Adverb
electronic signal	Yes	No	No	No
signal	Yes	Yes	Yes	No

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

Other hypernyms of electronic signal include sign, signaling, signalling.

electronic signal (noun)	signal (noun)
a signal generated by electronic means	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

electronic signal (adjective)	signal (adjective)
	notably out of the ordinary

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