Ultrarunning Glossary

The words the sport uses, in plain language: race formats, entry systems, and the vocabulary you'll meet on any race page or live tracker.

Ultramarathon: Any footrace longer than the 26.2-mile (42.2 km) marathon. The shortest standard ultra distance is 50 kilometers; the most iconic is 100 miles.
Aid station: A staffed checkpoint stocked with food, fluids, and often medical help. Races space them from a few miles apart to more than ten in remote terrain, and many double as timing checkpoints and cutoff points.
Backyard ultra: A last-one-standing race format: every hour, on the hour, runners start a 4.167-mile (6.7 km) loop called a yard. Miss a start or fail to finish a loop in the hour and you are out; the race ends only when one runner remains, and only that runner gets an official finish. The format began with Big's Backyard Ultra and its 4.167-mile loop, which makes exactly 100 miles per 24 hours.
Buckle: The traditional finisher award at 100-mile races is a belt buckle, not a medal. Some races grade them by time: at Western States, finishing under 24 hours earns the silver buckle.
Course record (CR): The fastest finish in a race's history, kept separately for men and women. Records are course-specific: when a race changes its route, direction, or distance, times are compared with care, and direction-specific records are labeled as such.
Crew: A runner's support team, who meet them at designated access points along the course with food, gear, and encouragement. Each race sets its own rules for where crews are allowed.
Cutoff: The time limit a runner must beat, at the finish and usually at intermediate checkpoints, to be allowed to continue. Missing a cutoff ends the race and records a DNF.
DNF: Did not finish: a runner who started but dropped, missed a cutoff, or was pulled. In hard mountain hundreds, a third or more of the field may DNF in a normal year.
DNS: Did not start: an entrant who never began the race.
Drop bag: A bag a runner packs before the race that the organization delivers to a designated aid station, holding spare shoes, clothing, lights, or food for later in the race.
Fixed-time race: A race scored by distance instead of time: run as far as you can in a set window such as 6, 12, or 24 hours, or 6 days, usually on a short loop or track. The winner is whoever covers the most distance. Across the Years runs formats from 24 hours to 6 days.
FKT: Fastest known time: the speed record for a named route outside of an organized race, such as a long trail or a mountain traverse, documented and verified by the community rather than a race clock.
Golden hour: The final hour before a race's overall cutoff, when the last finishers come in to the loudest support of the weekend. The best known is Western States' golden hour, between 29 and 30 hours.
Golden Ticket: An automatic entry to the Western States 100 earned by finishing at the top of a designated Golden Ticket race. Six races award them each season, two or three per gender, with unclaimed tickets rolling down the results.
Live tracking: Following a race in real time through checkpoint splits or GPS positions published by the race's timing platform, so spectators can watch the field move across the course. See what's live right now.
Lottery: How oversubscribed races select their fields: qualified applicants enter a draw, and odds often build with each consecutive unsuccessful year. Western States and Hardrock both fill this way.
Pacer: A companion runner allowed to accompany an entrant through later sections of a long race, for safety and morale. Each race sets where pacers may join, commonly around the halfway point of a 100-miler.
Running Stones: Lottery tickets for the UTMB World Series Finals in Chamonix, earned by finishing UTMB World Series races. More stones mean more entries in the draw for UTMB, CCC, and OCC.
Stage race: A multi-day race divided into daily timed stages, with cumulative time deciding the winner.
UTMB Index: A performance score UTMB assigns runners from their race results, by distance category. It seeds elite fields and gates entry standards at UTMB World Series events.
Vert: Cumulative elevation gain over a course, the sum of all climbing. A race's vert often says more about its difficulty than its distance: 100 miles with 33,000 feet of gain is a different sport than a flat 100.
Wave start: Starting the field in separate groups minutes apart to thin out crowded early trail. Each runner's time runs from their own wave's gun.
Yard: One loop of a backyard ultra: 4.167 miles, started on the hour, every hour. A finisher's result is their yard count; 24 yards is 100 miles in 24 hours.