Tennis Stringing Glossary
Short, plain definitions of the words players and stringers use. The two that cause the most confusion are reference tension, the setting you ask your stringer for, and stringbed tension, what the finished racquet actually holds. Each entry links to the guide that explains it in depth.
A
- Acoustic measurement
Estimating stringbed tension from the sound or vibration frequency produced when the strings are tapped. It is most useful for comparing repeated readings of the same racquet under similar conditions.
C
- Calibration
Adjusting a measuring tool or method against a known reference so its readings line up with that reference. Calibration improves consistency for one setup; it does not make a reading interchangeable with every other method.
- Cost per playing hour
The installed cost of a string job divided by the hours it stays playable for you. It lets you compare a cheap string that dies quickly with a dearer one that lasts longer.
- Crosses
The horizontal strings, woven over and under the mains from side to side. In a hybrid they can be a different string, gauge or reference tension from the mains.
D
- Dampener
A small rubber or silicone piece fitted between the strings near the throat to change the sound and feel of impact. Keep it on or off consistently when you take acoustic readings, because it changes the sound being measured.
- Dead strings
Strings that no longer give the response you want, even though they have not broken. Players usually notice a mix of lost control, harsher or vaguer feel, less snapback and measured tension change.
- Dwell time
How long the ball stays in contact with the strings during a shot, a few thousandths of a second. A softer stringbed lengthens it, which spreads the impact force over a longer time.
F
- Fresh-string baseline
A reading taken soon after stringing, with the same method you will use later. Every later reading is compared with this baseline rather than with the stringing-machine setting.
- Full bed
A setup that uses the same string in the mains and the crosses. It is the simplest setup to describe, repeat and compare.
G
- Gauge
The diameter of a string, given in millimetres or on the US gauge scale, where a higher number means a thinner string. Thinner strings are more flexible but usually less durable.
- Grommets
The plastic tubes and strips that line the holes in the frame and protect the strings from its edges. Worn or split grommets can damage strings and are worth checking when you restring.
H
- Head size
The area of the racquet’s hitting surface, usually given in square inches. At the same reference tension a larger head has longer strings and a softer stringbed than a smaller one.
- Hybrid setup
A setup with one string in the mains and a different string in the crosses, such as natural gut mains with polyester crosses. Record both strings, both gauges and both reference tensions so the setup can be repeated.
K
- Knot (tie-off)
Where a string ends and is tied off around another string at the frame. Knot positions are part of how a racquet is strung, so note them if a stringer changes them.
M
- Mains
The vertical strings, running from the head of the racquet to the throat. They are usually strung first and do most of the moving that produces snapback.
- Monofilament
A string made from one solid strand, as most polyester strings are. Monofilaments tend to be durable and firm compared with strings built from many fibres.
- Multifilament
A string made from many fine fibres twisted or bonded together, designed to feel softer and more elastic than a solid core. It usually frays visibly as it wears.
N
- Natural gut
A string made from animal intestine, today usually cow gut, prized for elasticity and for holding tension well. It costs more and is more sensitive to moisture than synthetic strings.
- Notching
Grooves worn into strings where the mains and crosses rub against each other. Deep notches are a sign of wear and often come before a polyester string breaks.
O
- Open and dense patterns
An open pattern has fewer strings and wider gaps, such as 16x19; a dense pattern has more, such as 18x20. Wider spacing lets strings move more and makes the stringbed softer at the same tension.
P
- Playing hours
The time a string job has actually spent on court. For active players it explains string wear and tension change better than the number of weeks since stringing.
- Polyester (co-poly)
A firm, durable string, usually a monofilament, often blended into a co-polyester. It tends to lose tension faster than nylon or gut and can feel dead before it breaks.
- Prestretch
Stretching a string before or while it is installed, by hand or with the stringing machine. Whether to use it is a choice for you and your stringer; record it so you compare like with like.
- Pro string setup
The strings, gauges and reference tensions a professional player is reported to use. It is context about one player’s choices, not a target for your own racquet.
R
- Racquet tension range
The range of reference tensions a frame maker prints on the racquet, for example 50–60 lbs. Staying inside it is the main guardrail when you choose a starting tension.
- Reference tension
The tension the stringing machine is set to pull each string to as it is installed, and the number you ask your stringer for. It is a setting, not a measurement of the finished stringbed.
- Relative change
The difference between a current reading and your fresh-string baseline, in lbs, kg or percent. Comparing a racquet with itself is more reliable than comparing readings from different tools.
- Restring window
The stretch of time when restringing makes sense for you, judged from playing hours, feel, visible wear and measured change. It is a personal range, not a single universal threshold.
S
- Snapback
Main strings sliding sideways during impact and springing back as the ball leaves. Smooth, well-seated mains move and return more easily than notched ones.
- String pattern
The number of main strings by the number of cross strings, such as 16x19. The pattern and head size together set how far apart the strings sit.
- Stringbed
The woven surface of mains and crosses that hits the ball. Its behaviour depends on the strings, their tension, the pattern and the frame together.
- Stringbed stiffness
How strongly the stringbed resists being pushed in by the ball. Higher tension, stiffer strings, denser patterns and smaller heads all make it stiffer.
- Stringbed tension
The tension the installed strings actually hold. It starts below the reference tension and keeps falling with time and play.
- Stringing machine
The machine that holds the frame and pulls each string to the reference tension. Different machines and techniques can give different stringbeds from the same setting, which is why consistent records matter.
- Synthetic gut
A general-purpose nylon string, usually a solid core with outer wraps. It is inexpensive and a common default for club players.
T
- Tension loss
The fall in stringbed tension after stringing, from relaxation under load and from impacts. It is fastest at first and differs by string material.
- Tension meter
A handheld or mechanical tool that estimates stringbed tension or stiffness by pressing on or measuring the strings. Like any method, its readings are most useful when repeated the same way.
- Tension units (lbs and kg)
String tension is given in pounds or kilograms; 1 lb is 0.4536 kg, so 55 lbs is about 24.9 kg. Always write the unit, because a bare number can be read either way.
Put the terms to work on your own racquet
Measure a fresh-string baseline, then follow the relative change as the same setup ages.
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