Rugby union is an outoor contact sport played with a prolate spheroid-shaped ball by two teams of 15 players. It is one of the two main codes of rugby football, the other being rugby league. There is also a seven-a-side variant named rugby sevens, which is played under modified rules and with only seven players per team. Rugby union is often referred to as simply rugby, or as football, and in regions where rugby league is played, as union.