Top definition
The hardened ridge of skin males develop on their index finger when turning off all the friggin' lights that the females of the house perpetually leave on.
Tony's LFC (lightswitch finger callus) was so developed that he could abrade the color off of a leather belt.
by geodave July 06, 2013
Get the mug
Get a LFC (lightswitch finger callus) mug for your dad Bob.