a term often used when having a thumb war. when your thumb is unnaturally larger than most peoples thumbs. Its what you choose to get when you are self concience about the freakishly large phalangie on your hand so you decide to "size it down". can also be used as a term to put down someone elses large hands.
dude seriously? yo mammas hands so big she needed some thumb reduction surgery!
by slyflyingninja December 27, 2011
Get the thumb reduction surgery mug.