distress signal vs distress call

distress signal and distress call both are nouns.

Word	Noun	Adjective	Verb	Adverb
distress signal	Yes	No	No	No
distress call	Yes	No	No	No

As nouns, distress signal and distress call are synonyms defined as:

distress signal and distress call: an internationally recognized signal sent out by a ship or plane indicating that help is needed

distress signal (noun)	distress call (noun)
an internationally recognized signal sent out by a ship or plane indicating that help is needed	an internationally recognized signal sent out by a ship or plane indicating that help is needed