Rosary piece (4)
I believe the answer is:
'rosary piece' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bead that I've seen before include "Item on a necklace" , "Drop of moisture; holed piece of glass" , "Glass ball" , "bit off necklace, say" , "Small round piece of glass" .)