Ball (in Mid. Eng. bal; the word is probably cognate with "bale," Teutonic in origin, cf. also Lat. follis, and Gr. πάλλα), any rounded body, particularly one with a smooth surface, whether used for games, as a missile, or applied to such rounded bodies as the protuberance at the root of the thumb or the big toe, to an enarthrosis, or "ball socket" joint, such as that of the hip or shoulder, and the like. A ball, as the essential feature in nearly every form of game requiring physical exertion, must date from the very earliest times. A rolling object appeals not only to a human baby but to a kitten and a puppy. Some form of game with a ball is found portrayed on Egyptian monuments, and is played among the least advanced of savage tribes at the present day. In Homer, Nausicaa was playing at ball with her maidens when Odysseus first saw her in the land of the Phaeacians (Od. vi. 100). And Halios and Laodamas performed before Alcinous and Odysseus with ball play, accompanied with dancing (Od. viii. 370). The Hebrews, the least athletic of races, have no mention of the ball in their scriptures.
Among the Greeks games with balls (σφαῖραι) were regarded as a useful subsidiary to the more violent athletic exercises, as a means of keeping the body supple, and rendering it graceful, but were generally left to boys and girls. Similarly at Rome they were looked upon as an adjunct to the bath, and were graduated to the age and health of the bathers, and usually a place (sphaeristerium) was set apart for them in the baths (thermae). Of regular rules for the playing of ball games, little trace remains, if there were any such. The names in Greek for various forms, which have come down to us in such works as the Ὀνομαστικόν of Pollux of Naucratis, imply little or nothing of such; thus, ἀπόρραξις only means the putting of the ball on the ground with the open hand, οὐρανία, the flinging of the ball in the air to be caught by two or more players; φαινίνδα would seem to be a game of catch played by two or more, where feinting is used as a test of quickness and skill.
Pollux (i. x. 104) mentions a game called ἐπίσκυρος, which has often been looked on as the origin of football. It seems to have been played by two sides, arranged in lines; how far there was any form of "goal" seems uncertain. Among the Romans there appear to have been three types or sizes of ball, the pila, or small ball, used in catching games, the paganica, a heavy ball stuffed with feathers, and the follis, a leather ball filled with air, the largest of the three. This was struck from player to player, who wore a kind of gauntlet on the arm. There was a game known as trigon, played by three players standing in the form of a triangle, and played with the follis, and also one known as harpastum, which seems to imply a "scrimmage" among several players for the ball. These games are known to us through the Romans, though the names are Greek. The various modern games played with a ball or balls and subject to rules are treated under their various names, such as polo, cricket, football, etc.
 Martial (iv. 19. 6) calls the harpastum, pulverulentum, implying that it involves a considerable amount of exertion.