Golf is a club-and-ball sport in which players use various clubs to hit balls into a series of holes on a course in as few strokes as possible. Unlike most ball games, golf cannot and does not utilize a standardized playing area, and coping with the varied terrains encountered on different courses is a key part of the game. The game at the usual level is played on a course with an arranged progression of 18 holes, though recreational courses can be smaller, often having nine holes. Each hole on the course must contain a teeing ground to start from, and a putting green containing the actual hole or cup 4.25 inches (11 cm) in diameter. There are other standard forms of terrain in between, such as the fairway, rough , bunkers (or "sand traps"), and various hazards but each hole on a course is unique in its specific layout and arrangement.
Golf is played for the lowest number of strokes by an individual, known as stroke play, or the lowest score on the most individual holes in a complete round by an individual or team, known as match play. Stroke play is the most common format.
The levels of grass are varied to increase difficulty, or to allow for putting in the case of the green. While many holes are designed with a direct line-of-sight from the teeing area to the green, some holes may bend either to the left or to the right. This is commonly called a "dogleg", in reference to a dog's knee. The hole is called a "dogleg left" if the hole angles leftwards and "dogleg right" if it bends right. Sometimes, a hole's direction may bend twice; this is called a "double dogleg".