Short for mustache. The term "mo" has gained notoriety and been propelled to international fame by the Movember movement.
Originated in Australia, Movember is an annual campaign to raise
money for mens' health issues; notably prostate cancer and testicular cancer. Every year men across the globe begin November 1 with a clean shaven
face and spend the month growing and grooming a mustache in an effort to raise awareness, and
money.