rosary vs prayer beads

rosary and prayer beads both are nouns.

Word	Noun	Adjective	Verb	Adverb
rosary	Yes	No	No	No
prayer beads	Yes	No	No	No

As nouns, rosary and prayer beads are synonyms defined as:

rosary and prayer beads: a string of beads used in counting prayers (especially by Catholics)

rosary (noun)	prayer beads (noun)
a string of beads used in counting prayers (especially by Catholics)	a string of beads used in counting prayers (especially by Catholics)