A baseball is a ball used in the sport of the same name. The ball comprises a rubber or cork center wrapped in yarn and covered with white horsehide or cowhide. A regulation baseball is 9–9+1⁄4 inches (229–235 mm) in circumference (2+55⁄64–2+15⁄16 in. or 73–75 mm in diameter), with a mass of 5 to 5+1⁄4 oz. (142 to 149 g). A baseball is bound together by 108 hand-woven stitches through the cowhide leather.
The leather cover is commonly formed from two peanut-shaped pieces stitched together, typically with red-dyed thread. That stitching plays a significant role in the trajectory of a thrown baseball due to the drag caused by the interaction between the stitching and the air.