To worry or be anxious; to fuss.

• To show irritation or peevishness.

To gnaw, erode, or wear away.

• To chafe or fray through rubbing.

To agitate or disturb a surface; to cause ripples.

• Of wind or tide: to roughen water.

A state of worry, irritation, or fuss.

• Anxious or peevish agitation.

A slight rippling or agitation on water or liquid.

• Foam or disturbance from fermentation.

A raised strip on a stringed instrument’s fingerboard.

• The space between two such strips.

To fit a fingerboard with frets.

• To press a string against a fret to change pitch.

Förster resonance energy transfer; fluorescence resonance energy transfer.