pronounced "baa-lous" - a contraction of the words Butt and Callous. A term describing the desensitization of the butt and groin that comes with sitting on a bicycle seat for extended periods. Without a proper ballous, cycling for long durations becomes extremely painful.
Floyd: Man- those guys on the Tour De France are impressive. They can ride for hour after hour on those crazy hard seats!
Greg: I know, I wish I had a ballous like that- I was riding last weekend and after several hours, I hurt so bad I couldn't sit anymore, but my legs were too tired to stand- It was like some medieval torture device!