bosu ball /ˈboʊsu ˌbɔl/ noun1 •A piece of exercise equipment with an inflated rubber dome attached to a rigid flat platform, used for balance training, strength exercises, or rehabilitation.Then you are an idiot who will always have stork limbs and a flabby body. Get back on your bosu ball. More protein won’t help this guy!! — 2016 formsbosu balls