| Bladed iron | A style of iron head that is usually forged from a stainless steel alloy and has a muscle-back head shape. |
| Bounce | The angle created between the front edge of a club's sole and the ground at address. A larger degree of bounce will prevent the club head from digging too deeply into the sand or turf. Wedges are offered at different bounce angles to accommodate differences in normal playing conditions and swing types. Generally, soft conditions and steeper swing planes benefit from more bounce. Whereas, less bounce is better for firmer playing conditions and shallower swing planes. |
| Bulge | Term used to describe the heel to toe curvature on the face of a driver, fairway wood, or hybrid. Bulge is used to compensate for mishits that cause hook or slice ball spin when the ball is struck on the heel or toe of the club. The greater the bulge (or curvature) the greater the compensation. |
| Cavity back | A term used to describe a style of irons that utilizes weighting around the perimeter of the club head to improve the forgiveness of the club when a ball is mishit and to better control ball launch angle. |
| Cast irons | An iron manufacturing process when heads are formed by poring molten steel into a mold and removed in one piece. |
| Center of Gravity (CG) | A term used to describe the theoretical point within a golf club head that represents the balanced point about which the head would rotate. Club manufacturers locate the center of gravity within a club head to control the launch angle of the ball. A lower CG will result in a higher ball launch angle when the ball is struck by the club head. |
| Club face | The hitting surface of a golf club. |
| Coefficient of Restitution (COR) | Is a measure of the efficiency of energy transfer when there is a collision between two objects (i.e. ball and club). In order to control the distance a golf ball can be hit, COR is measured and control both for both driver and golf ball designs. |
| Dimples | The indentations that cover a golf ball. Dimples are used to control ball aerodynamics. Changing the shape and depth of individual dimples (or the overall dimple pattern) has an effect on the flight of the ball. Generally, the depth of the dimples is inversely proportional to the height of the ball trajectory (i.e., deeper dimples result in lower trajectories). Changing the circumference and shape of dimples are other ways that manufacturers can produce different flight characteristics. |
| Flange | A term primarily used to describe the width of the sole of a sand wedge. |
| Forged irons | An iron manufacturing process when stainless steel is stamped, hammered, and ground into shape, with or without heat. |
| Frequency matched shafts | The process of ensuring that the shaft vibrations of all clubs in a given set match in frequency when struck. When the shaft frequencies are matched the feel is the same for each club. |
| Grooves | Narrow, etched lines on the face of an iron to enhance the spin when the ball leaves the club face. The size and shape of grooves are regulated by the rules of golf. |
| Hosel | The part of the clubhead into which the shaft is fitted and secured. |
| Launch angle | The angle at which the golf ball travels in relation to the ground immediately following impact. The ideal launch angle is dependent upon backspin, ball speed, and the club head design. |
| Leading edge | The forward edge of the club sole. |
| Lie angle | The angle formed between the center of the shaft and the ground line of the club when the club is soled in its proper playing position at address. Within a set of iron, the lie angle increases progressively through the set starting with the longest iron. Finding the proper lie angle is an important part of the clubfitting process. Taller golfers tend to require larger lie angles while shorter golfers tend to require lower lie angles in order to make the best contact with the ball. An improperly fitted lie angle will also cause sidespin at contact resulting in ball flights to be biased toward a hook or a slice. |
| Loft | A measurement, in degrees, of the angle at which the face of the club lies relative to a perfectly vertical surface. The loft angle affects how high and how far a ball will fly when struck. |
| Moment of Inertia (MOI) | The measure of a club head's resistance to twisting on off-center hits. |
| Multi-layer ball | A golf ball contructed using a solid core, an interior mantle layer, and soft exterior cover layer. The soft cover enhances feel, the firm inner mantle improves energy transfer to the core and the core itself promotes distance. All high performance balls use this construction. |
| Muscle back iron | A traditional bladed iron that positions the majority of the club head mass below the ball's center of mass at contact and are characterized by a relatively small sweet spot. |
| Offset | The distance from the front of the hosel to the club face. Most iron designs will have larger offsets for longer irons to make it easier to square the club face at impact. |
| Relief | The angling or curve up and back of the sole to reduce turf contact. |
| Shaft flex | The relative strength (stiffness or softness) of a club shaft. Appropriate shaft flex is determined by measured swing speed and swing tempo. |
| Shaft kickpoint | The point along the club's shaft length which exhibits the greatest amount of bend during the swing. The higher kickpoint shaft (i.e. located nearer to the grip) will decrease the ball launch angle. Whereas a shaft with a lower kickpoint (i.e. nearer to the club head) will increase ball launch angle. |
| Shaft torque | A measure of a shaft's resistance to twisting, expressed in degrees. Lower torque shafts feel stiffer and are generally preferred by players with higher swing speed. Torque has a minor effect upon trajectory, but has a large impact on the feel of shots struck off-center. |
| Sole | Bottom surface of a club head. |
| Sweet spot | The sweet spot defines the area on the club face that will produce optimal results when the ball contacted is within this region. The larger the sweet spot of a club, the more forgiving it is when a ball is mishit. The size of the sweet spot can be controlled by the distribution of mass in the club head. Perimeter weighting techniques are used to increase sweet spot size. |
| Swingweight | The measurement of a golf club's weight about a fulcrum point that is set at 14" from the grip end of the club. This standardized measurement representing how the weight of the club feels when the club is being swung. |
| Toe | The point of the club head farthest from the shaft. |
| Top edge | The top profile of an iron head. |
| Two-piece ball | A golf ball contructed using a solid core and exterior cover layer. |
