A tool used to measure one's feet for proper shoe size. The potential shoe buyer places his/her bare foot on a flat, marked plate, with the heel resting against a curved form on the back of the device. The big toe rests on a mark indicating the length size. The salesperson then slides an indicator against the outside of the foot to measure its width. The brannock device helps the salesperson verify the customer's totally incorrect estimate of their shoe size.
Customer (usually an extremely overweight woman holding a narrow black pump removed from a display): "I'd like to see these in a size 5, please."
Salesperson (usually some poor part-time high school student guy in an ugly tie who'd rather be at a rave or skateboarding): "Yes, ma'am. Why don't you have a seat here and we'll double check your size?"
Customer (eyeing the guy as he grabs the brannock device): "Oh, you don't need to measure. I've been a size 5 since I was 18."
Salesperson (thinking "Right, she's a size 5, and I'm Regis Philbin."): "Well, let's just check to be sure."
Customer (after squeezing her voluminous hoof into the brannock): "Was I right?"
Salesperson (trying to avoid a laughing fit): "Well, ma'am, it says you're a size 8. But don't worry. You're feet are probably a bit swollen from walking around the mall."
This was a common encounter during the worst job I ever had, shoe salesman at a Thom McAn store on Long Island. This job was directly responsible for my eventual enthusiastic enlistment in the United States Navy.