| No. | Item | Definition |
|---|---|---|
| 1. | 100-miler | race of about 100 miles |
| 2. | 100K | ultra race about 62 miles |
| 3. | 50K | ultra race about 31 miles |
| 4. | acclimation | adjustment to new conditions |
| 5. | aid station | race checkpoint with supplies |
| 6. | altimeter | tool measuring elevation |
| 7. | altitude | height above sea level |
| 8. | ascent | uphill section of trail |
| 9. | bailout | escape route off course |
| 10. | berm | banked turn on a trail |
| 11. | bib | race number worn visibly |
| 12. | blister | fluid-filled skin sore |
| 13. | bonk | suddenly run out of energy |
| 14. | buff | stretchy tube for head or neck |
| 15. | bushwhack | travel through unmarked vegetation |
| 16. | cadence | steps taken per minute |
| 17. | camber | sideways tilt of trail |
| 18. | chafe | skin irritation from rubbing |
| 19. | compass | tool showing direction |
| 20. | course | the marked race route |
| 21. | cramp | painful involuntary muscle tightening |
| 22. | creek crossing | place where trail crosses water |
| 23. | cutoff | latest allowed checkpoint time |
| 24. | dehydration | too little body fluid |
| 25. | descent | downhill section of trail |
| 26. | dew point | temperature where moisture condenses |
| 27. | DNF | did not finish |
| 28. | drafting | running behind to reduce wind |
| 29. | drop bag | stored race gear bag |
| 30. | effort | how hard you’re working |
| 31. | electrolytes | minerals lost through sweat |
| 32. | endurance | ability to sustain exertion |
| 33. | exposure | open terrain with drop-offs |
| 34. | false summit | apparent top before the real one |
| 35. | fire road | wide access road on trails |
| 36. | flagging | ribbons marking the trail |
| 37. | flask | soft bottle for drinking |
| 38. | footing | how stable the ground feels |
| 39. | fork | point where trail splits |
| 40. | fuel | food energy for running |
| 41. | gaiters | covers blocking debris from shoes |
| 42. | gel | portable concentrated energy food |
| 43. | GPX | digital route file format |
| 44. | grade | steepness of a slope |
| 45. | gravel | small loose stones |
| 46. | headlamp | lamp worn on the head |
| 47. | heatstroke | dangerous overheating illness |
| 48. | hill repeats | repeated uphill training efforts |
| 49. | humidity | amount of moisture in air |
| 50. | hydration | body’s fluid balance |
| 51. | hypothermia | dangerously low body temperature |
| 52. | intervals | repeated hard efforts with recovery |
| 53. | junction | place where trails meet |
| 54. | leave no trace | minimize impact on nature |
| 55. | ledge | narrow shelf of rock |
| 56. | lollipop | loop with out-and-back stem |
| 57. | long run | extended training run |
| 58. | loop | route ending where it started |
| 59. | map | drawn representation of terrain |
| 60. | mud | wet soft ground |
| 61. | negative split | faster second half than first |
| 62. | out-and-back | route returning same way |
| 63. | pacers | helpers running with a racer |
| 64. | pacing | controlling running speed |
| 65. | poison ivy | itch-causing plant |
| 66. | poles | sticks used for support |
| 67. | power hike | fast purposeful uphill walking |
| 68. | PR | personal best performance |
| 69. | recovery | easy rest after hard effort |
| 70. | reservoir | bladder holding drink in pack |
| 71. | ridgeline | top line of a ridge |
| 72. | rock garden | section packed with rocks |
| 73. | roots | exposed tree roots on trail |
| 74. | route-finding | choosing the correct way |
| 75. | runnable | easy enough to run |
| 76. | saddle | low point between peaks |
| 77. | scramble | climb using hands and feet |
| 78. | scree | loose small rocky slope |
| 79. | shell | light outer protective jacket |
| 80. | singletrack | narrow trail for one runner |
| 81. | stride | length and pattern of steps |
| 82. | summit | top of a mountain |
| 83. | switchback | sharp zigzag turn uphill |
| 84. | talus | slope of large loose rocks |
| 85. | technical | difficult, obstacle-filled terrain |
| 86. | tempo | comfortably hard sustained pace |
| 87. | threshold | hard pace you can sustain |
| 88. | ticks | small biting parasites |
| 89. | traction | grip between shoe and ground |
| 90. | trailhead | starting point of a trail |
| 91. | treeline | elevation above which trees stop |
| 92. | ultra | race longer than a marathon |
| 93. | vert | vertical gain climbed |
| 94. | vest | light pack for carrying gear |
| 95. | visor | brimmed headwear without a crown |
| 96. | warm-up | easy start before hard running |
| 97. | washout | eroded damaged trail section |
| 98. | watch | wrist device tracking run data |
| 99. | windchill | felt temperature lowered by wind |
| 100. | yield | give way on the trail |