recall vs call back

recall is a noun but call back is not a noun.

Word	Noun	Adjective	Verb	Adverb
recall	Yes	No	Yes	No
call back	No	No	Yes	No

As verbs, recall and call back are synonyms defined as:

Other synonyms of recall include call up, recollect, remember, retrieve, think.

As verbs, recall and call back are synonyms defined as:

As verbs, recall and call back are synonyms defined as:

Other synonyms of recall include call in, withdraw.

recall (noun)	call back (noun)
the act of removing an official by petition
the process of remembering (especially the process of recovering information by mental effort)
a call to return
a bugle call that signals troops to return
a request by the manufacturer of a defective product to return the product (as for replacement or repair)

recall (verb)	call back (verb)
recall knowledge from memory; have a recollection	recall knowledge from memory; have a recollection
cause one's (or someone else's) thoughts or attention to return from a reverie or digression	summon to return
go back to something earlier	return or repeat a telephone call
summon to return	cause to be returned
cause to be returned
make unavailable; bar from sale or distribution
bring to mind