Live Tennis APITennis data glossary: the terms in a scores and stats API
61 terms you meet in a tennis scores and stats API, each defined in a sentence or two you can quote. Every term shows the API fields it appears in and links the rulebook or reference behind it.
Download the CSVLicence: CC BY 4.0
Cite this page
Live Tennis API, "Tennis data glossary", livetennisapi.com/data/glossary, last updated 9 November 2026.
Each term has its own link. Add its anchor to the address, for example livetennisapi.com/data/glossary#walkover.
Rules of play come from the ITF Rules of Tennis and the ATP, WTA and Grand Slam rulebooks. Each rule links the book it was read in. Terms sourced to our API reference describe how our API uses them.
How does a match end, and what does each status mean?
- Match status#
Where a match is in its life: upcoming, live, completed or cancelled. A completed match can still have ended early, so read the outcome to see how it ended.
In the API:Match.status = "upcoming" Match.status = "live" Match.status = "completed" Match.status = "cancelled" Match.outcome Source: Live Tennis API reference, Match.status, Match.outcome
- Walkover#
A match that never began because the losing player was ill or injured, or was penalised or barred from playing before the first serve. It is not used when a lucky loser or alternate takes the place.
Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Walkover)
- Retirement#
A player stops after the match has started, because of illness or injury, and loses the match.
Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Retired)
- Default#
The losing player was defaulted under the Code of Conduct after the match had begun.
In the API:Match.outcome = "default" Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Default)
- Abandoned#
A match that began and will not be completed, for a reason other than a default or a retirement. There is no winner or loser.
In the API:Match.outcome = "abandoned" Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Abandoned)
- Suspended (interrupted) match#
Play has stopped during a match, for example because of rain, darkness or a medical reason. The match is paused and expected to resume.
In the API:Match.event_ status = "Interrupted" Event.type = "stoppage_ start" Event.type = "stoppage_ end" Source: Live Tennis API reference, Match.event_status
- Postponed#
A match moved to a later time or day.
Source: Live Tennis API reference, Match.event_status, Fixture.status
- Medical timeout#
Official time during a match to treat a medical condition. In ATP rules it is 3 minutes (4 and a half on a changeover) for each separate condition.
In the API:Event.type = "medical_ timeout_ start" Event.type = "medical_ timeout_ end" PlayerStoppage.kind = "medical_ timeout" Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Medical Time-Out)
What are tours, draws, rounds and entry types?
- Tour#
The circuit a match belongs to: the ATP Tour, the WTA Tour, Challenger level, the ITF World Tennis Tour or junior events. Challenger covers the ATP Challenger Tour and WTA 125.
In the API:Match.tour = "atp" Match.tour = "wta" Match.tour = "challenger" Match.tour = "itf" Match.tour = "juniors" Source: Live Tennis API reference, Match.tour
- Tournament tier#
The level a tournament was played at that season, such as a Grand Slam, an ATP Masters 1000 or a WTA 500. A tournament can change level between seasons.
Source: Live Tennis API reference, Match.tier
- Singles and doubles#
Singles is one player against one. Doubles is two against two. The API leaves the draw null when no source states which it is.
Source: Live Tennis API reference, Match.draw
- Main draw and direct acceptance#
The tournament proper. Players accepted straight into it on their ranking, or on a protected ranking, are direct acceptances.
In the API:Match.is_ qualifying Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Direct Acceptance)
- Qualifying and qualifier#
Qualifying is a separate competition before the main draw. Qualifiers are the players accepted into the main draw because they came through it.
Source: WTA Official Rulebook 2026, Appendix M, Glossary (Qualifier)
- Round#
The stage of a draw, named by players left: R128, R64, R32, R16, quarter-final (QF), semi-final (SF) and final (F). A qualifying semi-final is also SF.
In the API:Match.round Match.round_ code = "QF" Match.round_ code = "SF" Match.round_ code = "F" Match.is_ qualifying Source: Live Tennis API reference, Match.round_code
- Round robin#
A group stage where each player meets every other player in the group. The ATP Finals singles has two groups of four, then semi-finals and a final.
In the API:Match.round_ code = "RR" Source: ATP Official Rulebook 2026, Rule 4.01 A
- Seed#
A player given a preferred position in the draw because of their ranking. In ATP rules seeds follow the latest ATP Rankings, and a protected ranking is not used.
In the API:ArchivePlayer.seed Source: ATP Official Rulebook 2026, Rule 7.14
- Wild card (WC)#
A player chosen by the tournament director to fill a spot set aside in the draw.
In the API:ArchivePlayer.entry Source: WTA Official Rulebook 2026, Appendix M, Glossary (Wild Card)
- Lucky loser (LL)#
A player who lost in the last round of qualifying, or earlier if needed. A lucky loser can replace a main draw player who withdraws before their first match.
In the API:ArchivePlayer.entry Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Lucky Loser)
- Protected ranking (PR)#
A ranking given to a player who could not play any event for at least six months because of injury. It is used for entry, not for seeding. The WTA rules have a similar special ranking.
In the API:ArchivePlayer.entry Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Protected Ranking), and Rule 7.14
- Special exempt (SE)#
A main draw place for a player who missed this event's qualifying because they were still in the singles of another designated event that week.
In the API:ArchivePlayer.entry Source: ATP Official Rulebook 2026, Exhibit K, Glossary (Special Exempt)
How are points, games, sets and tie-breaks scored?
- Server and receiver#
The server puts the ball in play and the receiver returns it. At the end of each standard game the receiver becomes the server.
Source: ITF Rules of Tennis 2026, Rules 8 and 14
- Points in a game#
A standard game is scored love, 15, 30, 40, game, with the server's score called first. The API sends player 1 and player 2, in that order.
Source: ITF Rules of Tennis 2026, Rule 5a
- Deuce#
The score when both sides have won at least three points in a game and are level. In advantage scoring, a side must then win two points in a row to win the game. In no-ad scoring, the next point decides the game.
Source: ITF Rules of Tennis 2026, Rule 5a
- Advantage#
In advantage scoring, the score for the side that wins the point after deuce. If they win the next point too, they win the game. If not, it is deuce again. The API writes it "AD".
Source: ITF Rules of Tennis 2026, Rule 5a
- Set#
The first side to win six games with a two-game margin wins the set. In a tie-break set, a tie-break game is played at six games all.
Source: ITF Rules of Tennis 2026, Rule 6
- Tie-break#
A game played at six games all. Points count 0, 1, 2 and up, and the first to seven with a two-point margin wins the game and the set.
Source: ITF Rules of Tennis 2026, Rule 5b
- Match tie-break#
One tie-break game played instead of the deciding set, at one set all, or two sets all in a best of five match. First to ten points with a two-point margin wins.
Source: ITF Rules of Tennis 2026, Appendix VI, 4
- Final set tie-break#
A ten-point tie-break played at six games all in the final set, which decides the match. The four majors play one under the Grand Slam Rule Book.
In the API:Score.is_ tiebreak Source: Official Grand Slam Rule Book 2026, Grand Slam Regulations, Article I.L
- Best of three and best of five#
A best of three match is won by the first to two sets. Best of five is won by the first to three.
Source: ITF Rules of Tennis 2026, Rule 7
- Break of serve#
Winning a game in which your opponent served. Holding serve is the opposite: winning your own service game.
Source: Live Tennis API reference, Event, BreakPointResult
- Break point#
A point that wins the game for the receiver if the receiver wins it, such as 30-40. Up to three can be live at once.
Source: Live Tennis API reference, BreakPoint
What do the serve and return statistics measure?
- First and second serve#
If the first serve is a fault, the server serves again. Two faults in a row, a double fault, lose the point.
Source: ITF Rules of Tennis 2026, Rules 20 and 24a
- Ace#
A serve that wins the point without the receiver touching the ball.
Source: Live Tennis API reference, MatchStatisticsMeasured
- Double fault#
Two service faults in a row. The server loses the point.
Source: ITF Rules of Tennis 2026, Rule 24a
- First serve percentage#
First serves that landed in, as a share of all first serves.
In the API:MatchStatisticsMeasured.first_ serves_ in MatchStatisticsMeasured.first_ serves_ in_ of MatchStatisticsMeasured.first_ serves_ in_ pct Source: Live Tennis API reference, MatchStatisticsMeasured
- First serve points won#
Points the server won when the first serve went in, as a share of those points.
In the API:MatchStatisticsMeasured.first_ serve_ points_ won MatchStatisticsMeasured.first_ serve_ points_ won_ pct Source: Live Tennis API reference, MatchStatisticsMeasured
- Second serve points won#
Points the server won on a second serve, as a share of the points played on one.
In the API:MatchStatisticsMeasured.second_ serve_ points_ won MatchStatisticsMeasured.second_ serve_ points_ won_ pct Source: Live Tennis API reference, MatchStatisticsMeasured
- Service points won#
All points won while serving, first and second serve together, as a share of points served.
Source: Live Tennis API reference, MatchStatisticsSide
- Return points won#
Points won while receiving, as a share of points received. The measured stats split it by the server's first and second serve.
In the API:MatchStatisticsSide.return_ points_ won_ pct MatchStatisticsMeasured.first_ return_ points_ won_ pct MatchStatisticsMeasured.second_ return_ points_ won_ pct Source: Live Tennis API reference, MatchStatisticsSide
- Break points saved#
Break points a server faced and still won, as a count and a share of break points faced.
In the API:MatchStatisticsSide.break_ points_ faced MatchStatisticsSide.break_ points_ saved MatchStatisticsSide.break_ points_ saved_ pct Source: Live Tennis API reference, MatchStatisticsSide
- Break points converted#
Break points a receiver won, as a count and a share of break points they had.
In the API:MatchStatisticsSide.break_ points_ played MatchStatisticsSide.break_ points_ converted MatchStatisticsSide.break_ points_ converted_ pct Source: Live Tennis API reference, MatchStatisticsSide
- Hold and break percentage#
Hold percentage is service games won out of service games played. Break percentage is return games won out of return games played.
Source: Live Tennis API reference, MatchStatisticsSide
- Winner (shot)#
A shot that wins the point outright, with the opponent unable to return it.
Source: Live Tennis API reference, MatchStatisticsMeasured
- Forced and unforced error#
A point lost on a player's own missed shot. The scorer calls it forced when the opponent's shot caused it, unforced when not. In the API errors_total counts forced errors only.
In the API:MatchStatisticsMeasured.errors_ total MatchStatisticsMeasured.unforced_ errors_ total LivePoint.outcome = "forced_ error" LivePoint.outcome = "unforced_ error" Source: Live Tennis API reference, MatchStatisticsMeasured
How do rankings and ratings differ?
- ATP and WTA rankings#
The official tour tables, built from ranking points. In ATP rules they decide entry and seeding and count the past 52 weeks, with exceptions such as the ATP Finals.
In the API:Player.ranking Player.ranking_ points RankingRecord.system = "atp" RankingRecord.system = "wta" RankingRecord.rank RankingRecord.points Source: ATP Official Rulebook 2026, Rule 9.01
- Doubles ranking#
A separate table built from doubles results. In ATP rules it decides entry and seeding for doubles.
In the API:RankingRecord.system = "atp_ doubles" RankingRecord.system = "wta_ doubles" Player.doubles_ ranking Source: ATP Official Rulebook 2026, Rule 9.01 B
- ITF rankings#
The tables the ITF publishes for its own World Tennis Tour and junior events. They are separate from the ATP and WTA tables.
In the API:RankingRecord.system = "itf_ mt" RankingRecord.system = "itf_ wt" RankingRecord.system = "itf_ jt" Player.itf_ ranking Source: Live Tennis API reference, RankingRecord.system
- Elo rating#
A strength rating that moves after each match by how far the result differed from what the two ratings expected. Ours starts at 1500 on four ladders: all surfaces, hard, clay and grass.
In the API:RankingRecord.system = "elo" RankingRecord.rating RankingRecord.surface RankingRecord.matches Source: Live Tennis API reference, RankingRecord
- Rating and ranking#
A ranking is a position on a table built from points. A rating is a number that estimates strength. Elo is a rating with no points. It gets a rank only in a ranked listing.
Source: Live Tennis API reference, RankingRecord
What are head-to-head records and court surfaces?
- Head-to-head (H2H)#
The record between two players: how many times each has beaten the other. Meetings with no known winner are counted apart as undecided.
In the API:GET /h2hHeadToHead.totals. p1_ wins HeadToHead.totals. p2_ wins HeadToHead.totals. undecided HeadToHead.by_ surface Source: Live Tennis API reference, HeadToHead
- Court surface#
ATP rules class outdoor courts as hard, clay or grass. The API uses those three values with a separate indoor flag, and null when no source states one.
In the API:Match.surface = "hard" Match.surface = "clay" Match.surface = "grass" Match.indoor Tournament.surface Source: ATP Official Rulebook 2026, Rule 6.01 A
What do the live and point-by-point fields mean?
- Point-by-point data#
One row for each point played, in order, with the score after that point.
Source: Live Tennis API reference, LivePoint
- Sequence number#
A per-match counter that orders score states and points. Order and de-duplicate on it, never on timestamps.
Source: Live Tennis API reference, Score.sequence, LivePoint.seq
- Point outcome#
How a point ended: ace, double fault, winner, forced error or unforced error. It is null when the source did not say.
Source: Live Tennis API reference, LivePoint.outcome
- Stale score#
A live score that has not changed for longer than expected. The API flags it and says how many seconds have passed since the score last changed.
Source: Live Tennis API reference, Score.stale, Score.age_seconds
- Observed and reconstructed rows#
An observed row was recorded while the point was played. A reconstructed row was rebuilt later from a finished match record, so it has no timestamp.
Source: Live Tennis API reference, HistoryTapeRow.origin
- Win probability#
Our model's estimate of the chance that player 1 wins the match, updated as the score changes.
Source: Live Tennis API reference, Score.win_probability_p1
What do the market price terms mean?
- Match-winner market#
A prediction market on who wins the match. Each side trades at a price between 0 and 1. It is not an official line and can lag the live score.
Source: Live Tennis API reference, Market, Price
- Bid, ask, mid and spread#
The bid is the highest price a buyer offers and the ask the lowest price a seller offers. The mid is halfway between them, the spread the gap.
Source: Live Tennis API reference, Price
- Implied probability#
A price between 0 and 1 read as the market's chance that a side wins. It comes from trading on the market and can lag the live score.
In the API:Price.mid Source: Live Tennis API reference, Price
- Synthetic quote#
A quote whose bid and ask were estimated from the mid because no live order book was read. The mid is still the observed one.
In the API:Price.synthetic Source: Live Tennis API reference, Price.synthetic
Can I reuse the definitions?
Yes. The CSV is under CC BY 4.0, so you can copy and adapt it, commercial use included, with credit to Live Tennis API. A credit line that works is "Tennis data glossary: Live Tennis API (livetennisapi.com/data/glossary), CC BY 4.0."
The CSV has one row per term, with the columns category, term_id, term, definition, api_fields, source_name, source_url, source_section and checked. It is UTF-8 with a header row.
Looking for the short codes instead, like R16, W35 or BO5? The tennis data codes index lists tours, rounds, surfaces and match formats. The score notation comparison shows how points are written down.
Spotted a definition that is wrong or out of date? Write to hello@livetennisapi.com and we will check it.
Last updated 9 November 2026. Every source was read on 9 November 2026.