bubble
n.β Β«In NFL scouting parlance it is referred to as a “bubble.” You and I call it a butt or backside or rump. If youβre an NFL lineman, the bigger the bubble, the better, because it makes you tougher to move. Eagles defensive tackle Corey Simonβs bubble is, for lack of a better word, significant.Β» ββSmith believes 49ers made a smart choice” by Paul Domowitch Philadelphia Inquirer (Pa.) Apr. 25, 2005. (source: Double-Tongued Dictionary)