The scientific theory that allows a male to determine a female's figure and/or bodytype based solely on the size, shape, and density of her arm. The male is able to determine whether she is fit, skinny, fat, or even skinny fat based on a single glance.
If her arm is super thick but she still has a pretty face then Arm Theory states that she is better labeled as "fat" and not as "pretty."
by Delicious D February 15, 2008
The circumference of a female's upper arm can determine how much she will weigh in the future. A larger circumference predicts a woman will gain weight uncontrollably as she ages, while a smaller circumference predicts that she will keep her petite figure without much effort.
by AphtorShok August 28, 2006