Golf is a sport in which players (golfers) using many types of clubs, attempt to hit balls into each hole on a golf course in the lowest possible number of strokes. Golf is one of the few ball games that do not use a standardized playing area; rather the game is played on golf "courses", each one of which has a unique design and typically consists of either 9 or 18 holes. Golf is defined in the Rules of Golf as "playing a ball with a club from the teeing ground into the hole by a stroke or successive strokes in accordance with the Rules". Golf competition is generally played for the lowest number of strokes by an individual, known simply as stroke play, or for the lowest score on the most individual holes during a complete round by an individual or team, known as match play.
The rules of golf  are internationally standardized and are jointly governed by the Royal and Ancient Golf Club of St Andrews (R&A), which was founded 1754 and the United States Golf Association (USGA).
The underlying principle of the rules is fairness. As stated on the back cover of the official rule book: Play the ball as it lies, play the course as you find it, and if you cannot do either, do what is fair.
There are strict regulations regarding the amateur status of golfers. Essentially, anybody who has ever received payment or compensation for giving instruction or played golf for money is not considered an amateur and may not participate in competitions limited solely to amateurs. However, amateur golfers may receive expenses which comply with strict guidelines and they may accept non-cash prizes within the limits established by the Rules of Amateur Status.
In addition to the officially printed rules, golfers also abide by a set of guidelines called golf etiquette. Etiquette guidelines cover matters such as safety, fairness, easiness and pace of play, and a player's obligation to contribute to the care of the course. Though there are no penalties for breach of etiquette rules, players generally follow the rules of golf etiquette in an effort to improve everyone's playing experience.
Penalties are incurred in certain situations. They are counted towards a player's score as if they were an extra swing or swings at the ball. Strokes are added for rules infractions, or for hitting one's ball into an unplayable situation. A lost ball or a ball hit out of bounds result in a penalty of one stroke and distance. (Rule 27-1) A one stroke penalty is assessed if a players equipment causes the ball to move, or the removal of a loose impediment causes the ball to move. (Rule 18-2) If a golfer makes a stroke at the wrong ball (Rule 19-2), or hits a fellow golfer's ball with a putt (Rule 19-5), the player incurs a two stroke penalty. Most rule infractions lead to stroke penalties, but also can lead to disqualification. Disqualification could be from cheating, signing for a lower score, or from rules infractions that lead to improper play.