WEEK 5 — PARTNERS
A "partner" is a player associated with another player on the same side.
In a threesome, foursome, best-ball or four-ball match, where the context so admits, the word "player" includes his partner or partners.
— Rules of Golf, Definition of "Partner"
Four-ball competitions (both match play and stroke play) are commonly played. In a four-ball, two players (the side) compete as partners each playing his own ball and the side's score for a hole is the better score (net, in a handicapped competition) of the two players.
Less common forms of partnership play are foursomes (where two players comprise a side and alternate strokes with a single ball in either stroke play or match play), threesomes (where two players play, alternating strokes with a single ball, when competing in match play against a single player), and best-ball (where a single player plays a match against the better ball of two or three other players).
A player only has a partner when competing in one of these forms of play. If the form of play is individual stroke play in which the scores of a team's members are added together to make up the team's score, the players are not partners under the Rules of Golf.
"Choose your friends [partners] wisely."
Rule 8-1 authorizes a player to give advice to or receive advice from his partner. This exchange of advice may be the most beneficial aspect of having a partner (though a partner who makes a lot of birdies is always useful). Additionally, the partners may share clubs provided the total number of clubs carried by those partners sharing the clubs does not exceed 14.
Along with the beneficial aspects of having a partner come additional responsibilities. As the Definition of "Partner" explains, the word 'player' in the Rules of Golf includes the player's partner (in most cases*); thus a partner's actions could cause the player to incur a penalty. Let's look at a few examples for four-ball play:
*Rule 20-2a explains that the player himself must drop the ball; this is a case where the word "player" does not include the player's partner.
Reprinted with permission from the USGA.