A bead used to be a prayer. The Old English was gebed, from an old root that meant to ask, the same root that sits under the German bitte. Then people began keeping count of long runs of prayers on strings of small pierced balls, one ball for each prayer, and somewhere around the fourteenth century the word slid along the string, from the thing you said to the thing you held while you said it. By now it has gone all the way: a bead of sweat, a bead of glue, a bead of rain on a window, none of them asking anybody for anything. That is what tends to happen to whatever you keep your place with. After long enough you stop noticing what it was counting, and only notice the counter.