Tennis String Glossary

Actual Tension.  The tension in a strung racquet, which will almost always be lower than the machine setting, or reference tension.  This is due (mostly) to string relaxation, or creep.  As a result, a racquet strung at 60 pounds may actually measure (with a Stringmeter) 50-55 pounds, depending on head size, type of string, and machine type used.

Cross-Section.  The width/diameter of a frame or string.  Usually measured in millimeters.  A thicker cross-section string will be more durable than a thinner string, all things being equal.

Damping (or Dampening).  Generally refers to vibration and/or shock damping and can apply to the racquets or strings.  Rubber string dampers reduce string vibration only; they have no effect on frame shock or vibration.

Elasticity.  Often used term to describe a string's stretchiness and comfort.  In strings, the ability of a string or web of strings to return to it's original position after ball contact.  Factors that influence this include string material, construction, gauge, and tension.  Over time, strings lose tension and elasticity, making them play dead and requiring more effort from the player.

Gauge.  Standard U.S. measure of string thickness.  Most tennis strings are 15-17 gauge, with a few specialty strings being 18-20 gauge.  The higher the gauge number, the thinner the string and typically measured in millimeters.  Half-gauges are represented by the letter L, for "light".  A 15L is between a 15 and 16 gauge.  Thinner strings offer greater feel, power, and spin potential than a thicker string of the same material and construction.  Although the Tennis Industry Association has standardized gauge specifications, don't assume that all 16 gauge strings (or 17, 18, etc.) are created equal.  One company's 16 gauge string may measure 1.25 mm, while another will measure 1.32 mm, which represents almost a half gauge difference.

Hybrid Strings. The combination of any two string types and/or gauges, one for the mains and one for the crosses.

Reference Tension.  The tension a racquet is strung at, or machine tension, which is always higher than Actual Tension.  Continuous pull stringing machines (electric, electronic and dropweight) will generally string tighter (5-10%) than a lockout (spring tension) machine, ATBE.

Resilience.  A commonly used term to describe string responsiveness.  Similar to elasticity, a more resilient string is more responsive or lively, providing greater ball speed or power.  Specifically, resilience is the speed at which strings (or web of strings in a strung racquet) return to their original position after contacting the ball.  Over time, strings lose their resilience, returning less energy to the ball.  This loss of resilience causes the strings to play "dead".