String Terms

Core
The center strand or strands of a synthetic string.

Cross Strings
Strings installed horizontally, as seen when facing the frame with the handle pointing down. Commonly installed after the main strings.

Elasticity
The ability of the string to return to its original shape and condition after striking the ball.

Fan Pattern
Any string pattern in which the cross strings do not intersect the main strings at 90 degrees. In typical fan patterns, the main strings are closer together at the throat than at the tip.

Gauge
A number used to represent string diameter. Most tennis strings are 15 to 18 gauge, The higher the number, the thinner the string. They are usually measured in millimeters. Half-gauges are represented by the letter L, for "light". A 15L is between a 15 and 16 gauge.

15 G. The thickest
16 G.
17 G.
18 G. The thinnest

Hybrid
A string set comprising two different types or gauges of string, such as gut and aramid. One type of string is used for the mains and the other is used for the crosses.

Kevlar
A trademarked name for aramid fibers twisted together to form string or bonded in resins in the manufacture of frames.

Main String
Strings installed vertically, as seen when facing the frame with the handle pointing down. Commonly installed before the cross strings.

Monofilament
Synthetic string composed of only one strand, which may or may not have a coating.

Multicore
Synthetic string with a core composed of multiple strands. Some multicore strings have two or more multi-strand bundles.

Multifilament
Synthetic string with many fibers twisted together, usually without a single, large strand at the core.

Multiwrap
Synthetic string with multiple layers wrapped around a core.

Natural Gut
String made from beef intestines, which are cleaned, stretched, and twisted together.

Nylon (also called polyamide)
The most common material used in the manufacture of synthetic strings.

One-Piece
A method of stringing a frame so that only one piece of string is used, resulting in only two tie-off knots.

Pattern
The numbers of mains and crosses to be used in a specific frame.

Polyester
A synthetic string material offering greater durability than nylon.

Polyurethane
A thin, protective sheathing applied to the outside of a string or to individual strands that make up a string.

Rough
A string with purposely stippled, grooved, or striated coatings, with outer filaments of slightly different size, or with natural surface texture (such as natural gut or uncoated multifilaments).

Shared Hole
A grommet through which two strings must pass, such as one main and one cross string, two mains, or two crosses.

Smooth
A string with little or no surface texture, bumps, or ridges, and with uniformly sized filaments and a round cross section.

Solid Core
The single, large center strand of a synthetic string with wrap(s).

Stencil
A racquet or string manufacturer’s logo, cut into a thin piece of plastic. The stencil is held against the string bed, and ink is applied through the opening of the stencil to mark the stringbed with the logo.

Stringbed
The hitting surface of the racquet. The stringbed shall not exceed 15.5 inches in overall length, and 11.5 inches in overall width.

String Savers
Small nylon or Teflon inserts that can be installed between main and cross strings to prevent wear at intersections.

Stringbed Density
The number of mains and crosses per square inch of the stringbed.

Synthetic Gut
String made from manmade materials such as nylon, polyurethane, aramid, polyester, Zyex, etc.

Tension Range
A manufacturer’s suggested high and low values for the tensions in stringing their racquets. Exceeding these values will void a racquet’s warranty.

Texture
A descriptive term relating to the surface features of string. The two most common categories are smooth and rough.

Trampolining
The springy reaction of the ball coming off the stringbed.

Tubing
Short pieces of hollow Teflon or nylon through which the string is threaded before insertion into a rough, broken, or missing grommet, when the grommet itself cannot be replaced.