ETYM Old Eng. fretten to adorn, AS. fraetwan, fraetwian; akin to OS. fratahôn, cf. Goth. us-fratwjan to make wise, also AS. fraetwe ornaments, OS. fratahî adornment.
1. To be agitated or irritated.
2. To carve a pattern into.
3. To cause annoyance in.
4. To decorate with an interlaced design.
5. To wear away or erode; SYN. eat away.

ETYM French frette a saltire, also a hoop, ferrule, prob. a dim. of Latin ferrum iron.
1. A small bar of metal across the fingerboard of a musical instrument; when the string is stopped by a finger at the metal bar it will produce a note of the desired pitch.
2. Agitation resulting from active worry; SYN. stew, sweat, lather, swither.
Inlaid ridge of ivory or metal, or a circlet of nylon, on the fingerboard of a plucked or bowed string instrument, against which a string is pressed to change pitch.