A flagstick is exactly that: a stick with a flag on it*. You see them on putting greens to mark the location of the hole. Some courses color code the flags on flagsticks to denote if the hole location is near the front, center or back of the green. Another way of doing the same thing is to put the flag high, middle or low on the stick. (A course that does this should note the practice on its scorecard or pin sheet.)
One of the most important things to know about the flagstick, in terms of its impact on your game, is that it is a penalty for the ball to enter the cup with the flagstick still in the hole for any stroke played from the surface of the putting green.
In the golf rules, situations involving the flagstick are covered in Rule 17 — for example, when the flag should be removed, what happens when a golfer removes the flag without authorization, what to do if the ball hits the flagstick or lodges against it, etc. See Rule 17 for rulings on those and other flagstick-related scenarios.
(*Note that a flagstick does not have to have a flag, or banner or bunting, flying at its top. Rarely, golfers encounter other items at the top of the flagstick, such as wicker baskets at Merion Golf Club.)
Definition of ‘Flagstick’ from The Rules of Golf
The official definition of flagstick from the Rules of Golf includes some information about the specific shape of the flagstick. Here is that definition, from the USGA/R&A:
The “flagstick” is a movable straight indicator, with or without bunting or other material attached, centered in the hole to show its position. It must be circular in cross-section. Padding or shock absorbent material that might unduly influence the movement of the ball is prohibited.
The rules do not require that the flagstick be any specific height, but the USGA recommends a flagstick height of at least seven feet.
‘Flagstick’ vs. ‘Pin’
“Flagstick” and “pin” are synonyms and are used interchangeably by golfers. (“Flagstick” is often shortened to just “flag,” too.) However, the governing bodies always use flagstick, never pin. So you might say that flagstick is the technically accurate term of the two words.
The Flagstick In Play
One of the things about the flagstick and its role in golf that might perplex newcomers to the game is the practice of “tending the flagstick.” That means that one golfer stands next to the hole and holds the flagstick, then removes it before the other golfer’s putted ball reaches the hole. There are certain rules and issues of etiquette surrounding this practice that are covered in our FAQ on the subject, How to Tend the Flagstick and When to Request It.