A playoff in the sport of golf is an extra hole, or holes, played when, at the completion of regulation play in a competition or tournament, there is a tie and it is desirable to determine an outright winner.
Playoffs are a common occurrence in professional
tournaments when the players are readily available to participate at
the completion of normal play. However in most amateur tournaments, and
particularly in club competitions, that is not the case and other
methods may be used to determine the winner, such as scorecard count
back, whereby the player with the lowest cumulative score over the last
18, 9, 6, 3 or 1 hole(s) is declared the winner.
Source: wikipedia.org : technical writer