This is the place to learn all the latest trail lingo. I am always adding new info. If you know of a word that is not on here, leave me a comment with the word and a description and I'll see that it's added to the list.
ABC
Advance Base Camp. A lesser-equipped, less-comfortable camp serving as a launch pad higher on a mountain.
Abney Level
Hand-held instrument used by trail builders for measuring angles of elevation or inclination of trail.
Access Trail
Usually connects a primary trail to a road, campground, etc. or another trail.
Accessible
Trail that complies with the Americans with Disabilities Act (ADA) Accessibility Guidelines and can be better used by people with disabilities.
Acclimatization
Process of becoming gradually accustomed to high altitude.
Adopt-A-Trail
Individuals, groups or businesses “adopt” trails, volunteering for periodic maintenance, litter removal, etc. Usually accompanied by pleasant signs.
Airline
A trail that runs more or less straight regardless of how steep the terrain is. As if you drew a line through the air, rather than use switchbacks or contouring to get from point a to point b.
AMC
Appalachian Mountain Club. Group headquartered in Boston that controls the hiking trails on the White Mountains. The Forest Service controls access, the AMC owns the huts and controls the traffic. The huts are a series of buildings at or above timberline where hikers can buy a meal, relax, refresh, and stay overnight if they so desire.
AMS
Acute Mountain Sickness. Occurs at high altitude due to diminished oxygen. Begins with shortness of breath, followed by swelling, flu-like symptoms, and eventually, death. Most people won’t experience symptoms until they reach heights well above 10,000 feet. Varies with the individual.
Apron
Transition area on a switchback.
ArĂȘte
A steep ridge; pointy.
Armoring
Covering on a trail surface...rock, brick, stone, concrete, or other material.
"AT"
Appalachian Trail.
AYCE
Stands for "all you can eat" restaurant.
Backcountry
Area where there are no maintained roads or permanent buildings—just primitive roads and trails.
Backslope
Trail construction term. Describes the cut bank along the uphill side of the trail, extending upslope from the tread (the part of the trail you walk on).
Bald
Describes a treeless, rocky summit in certain areas of the Appalachians. A "bald" is usually a treeless summit in the southern region that is not necessarily above timberline, but the peak is still open at the summit. Has more of a pastoral feel than the treeless summits of the Whites or Adirondacks.
Base
Primary excavated bed of a trail upon which the tread, or walking surface lies.
Base Course
Layer material placed on a trail bed to support surfacing. Trail construction term.
Bear Bagging
The practice of hanging food up off a tree branch so that a bear can't get to it
Bear Box
Metal containers found at trail heads where bears are active. The idea is to take all food and other smelly stuff out of your car and leave it in the bear box. These boxes use latches, pins, or other devices that require human dexterity in order to open them.
Bed
Excavated or cleared surface on which a trail lies.
Bench
A long step, or tier, on the side of a hill. You climb until you reach the bench, then you walk across it, then climb until you reach the next bench.
Bivouac
A temporary or emergency "camp" or shelter, usually made in an undesirable locale on the side of a mountain, cliff, or in other such conditions where the hiker or climber requires rest overnight or during harsh conditions.
Bivy
A sort of tent/sleeping bag cover for emergency shelter.
Black-Blazer
Someone -- usually a disgruntled townie -- who paints over or otherwise removes trail markers to prevent hikers from finding the trail.
Blaze
Metal, paint, rock, or plastic tags nailed to trees to mark a trail.
Blow down
Trees or whatnot "blown down" by wind and now blocking the trail.
Blue-Blazer
Term used by "thru-hikers" to describe those who will use shortcuts, connector trails, alternative trails, etc. periodically for a change of pace or break from monotony.
Bluff
A promontory, riverbank, cliff, etc. that is too steep to walk down without handholds or a switchback trail.
Boardwalk
Planking built on pilings in areas of wet soil or water to provide dry hiking.
Bog Bridge
Logs that lie in the swamp, like puncheons (see) to provide semi-dry hiking.
Bollard
Round post barrier, often metal, usually 4' high, to prevent vehicles from entering a trail.
Borrow
Fill used in trail construction, obtained from a nearby location, usually leaves small pits behind.
Braided Trail
Numerous routes have been created, usually at access points or where shortcuts are easy, resulting in excess wear and innumerable little trails crisscrossing randomly every few feet. An infamous example of braiding is found at Landscape Arch, Arches National Park. (Access has since been limited due to partial collapse)
Brushing-In
Using logs, branches, rocks, etc. to obstruct a closed section of trail to prevent future use.
Bushwhacking
Going off the trail, in the interest of taking a shortcut, creating a trail, looking for a rumored location, etc.
Cache
A hidden stash of food or supplies, left along a trail for return or future use.
Cairn
A pile of rocks used to indicate direction of a trail in a treeless area; usually above timberline or in canyon country.
Canopy
Upper layer of leaves in a forest, covering the ground below.
CDT
Continental Divide Trail
Cirque
A group of mountains that forms a circle.
Class
Usually referred to in terms of technical climbing, for example, Class 1 is a simple mountain that can be climbed wearing a pair of sneakers -- little more than a nature loop. Class 2 includes minor handholds, more or less to steady yourself as you clamber up the mountain. Class 3 includes some vertical climbing, and perhaps use of a rope. Class 4 is any climb that requires use of a belay, in which another climber is required to remain stationary to take up slack and arrest the fall of the active climber. Class 5 is any climb that requires ropes to be attached to fixed objects, such as a tree or piton. The attachment is not to aid in ascent, but rather to protect in the event of a fall. Class 5 is the one with the most "variables." A Class 5.0 has two handholds and two footholds. Class 5.4 is missing a hold. Class 5.8 has a hold available for one hand and one foot only. Class 5.12 has no visible holds. Class 5.13 is a surface with no holds and is under an overhang. Class 5 is often further broken up, such as 5.13a, but this arcane is really in the climber's arena...not ours. Class 6 is any climb that requires artificial assistance to be carried out, whether it is ropes dropped from above or other mechanical aids.
Col
A "pass" or low, sometimes protected area on a massif (mountain range).
Contouring
Following an imaginary contour line around a mountain or canyon to get from point a to point b, rather than going up and down on a direct path. When a trail is "contouring" it means that it's relatively flat, and going around a promontory rather than over it. The Tonto Trail in the Grand Canyon is a well known "contour" trail...
Cornice
An overhang of ice or snow on the crest of a ridge or mountain. Caused by wind. Suggestion: Don't stand on a cornice.
Couloirs’
A gully on a mountainside. Could be a gully in the ground, or in snow.
Crampons
Sharp, pointy things that can be strapped to your boots, used for moving about on ice or steep ice/snow surfaces.
Craps Out
The trail grows faint, and then ends. Also used by climbers and cavers when a particular route can no longer be followed, or cave dead ends.
Death March
Unusually long, not very interesting hike. Term often applied when forced to take a dull trail to reach the one you really want to be on.
Double blaze
Two blazes, one atop the other, which denotes a change in direction or junction in the trail coming up. When the top blaze is to the right, it means the trail turns right, etc.
False Lead
A spot that looks like the trail but is in fact a dead end or the trail craps out.
Fast packing
Intentionally running the length of a hiking trail to establish and compete against your personal best time and sometimes to compete against times established by others.
Fen
Low, flat, marshy land or a bog.
Flail
When a tired hiker who is no longer paying attention gets turned off the true trail by a false lead.
Flip-flop
Mostly used with the Appalachian Trail. Describes a thru-hiker who realizes he won't finish before it snows up North, gets a ride to Katahdin and hikes back to where he left off.
Forty-sixer
Peak bagger slogging up the 46 highest peaks in New York's Adirondacks. One of the better-known peak bagging milestones.
Fourteener
Peak bagger pursuing the Colorado Mountains exceeding 14,000' elevation.
Free hiking
Hiking off of established trails. Unlike "bushwhacking" this is usually done as a short-cut, free hiking intentionally seeks a complete hike experience free of artificial boundaries. Some fast packers are also free hikers.
Gaiters
Outerwear that zips or snaps around ankles and lower legs to keep water, snow or muck out of your climbing boots.
Ghost-Blazing
The art of following a section of trail that is no longer used. When a trail is "re-routed," usually the old blazes are blackened out.
Glonk
A clueless idiot who doesn't realize that uphill hikers have the right of way on a trail, and just bulldozes down.
GORP
Originally an acronym for Granola, Oats, Raisins, Peanuts. More commonly known as "Good old raisins and peanuts."
Goes
Adjective to describe a lead (faint trail during a bushwhack, unexplored part of a cave, route up a rock face) that pans out, or "goes" where you hoped it would, rather than dead-ending.
Half Bench
Type of trail where half of it is excavated out of the slope and the outside of the trail tread contains the excavated material. Trail looks as if it were chipped out of the side of the hill, which is what it is.
Herd Path
An unofficial but obvious route hikers use to get from one place to another. Sometimes refers to an official path that is extremely overused.
IAT
International Appalachian Trail. Starts In Northern Maine and ends in Morocco.
Knob
Prominent rounded hill or mountain. Common term in the southeastern USA
Lean-to
One- to three-sided structure, usually with a single slanted roof, designed to provide minimal shelter for backpackers.
MUDS
Mindless up and downs. Where the trail goes up and back down for no reason other than the amusement of whoever laid out the trail.
Nobo
North bounder (AT or PCT)...
Pack-out
Also known as "carry-out." The practice of leaving nothing -- and that does mean nothing -- behind on a backpacking trip. Require Ziploc bags, PVC tubes with caps, etc.
Path
A small, short trail that is used in the place of a road. It usually serves to link tow busy areas of a town.
PCT
Pacific Crest Trail
Peak bagging
Chasing your personal checklist of peaks. Organized peak bagging lists, such as "White Mountain 4000 footers" are popular; there are a number of clubs that promote and recognize peak bagging accomplishments.
Point
Lead person in a line of hikers. Responsible for following the trail.
Puncheons
Logs, planks, rocks, or other crude "bridges" built across soggy areas.
Prescribed burns
Intentional fires conducted by forestry services to clear underbrush and eliminate some of the fuel for potentially larger unintentional fires. These used to be called "controlled burns" but since they seldom are, the name was changed.
Rainbow-Blazer
Term used by "thru-hikers" to describe people who hook together all sorts of routes to complete a trail -- including hitch-hiking.
Roller Coaster
Trail that goes up and down like a series of waves.
Scramble
Has a couple of meanings in hiking circles. Generally, to climb in a hurried, helter-skelter fashion, having to use your hands. If it's a climb you probably could do without your hands, but you feel compelled to use them, it likely classifies as a scramble. Scramble also refers to a group of climbers going up a slope using all sorts of routes, sort of a "get up however you can since there's no trail here and we'll meet at a certain point."
Scree
The sort of stuff found on a talus slope...loose rocks, scrabbly, hard to get good footing on.
Seven Summits
Refers to the highest summits on the main seven continents; a goal of many wealthy adventurers is to reach all seven summits.
Shelter Rat
Usually refers to thru-hikers, shelter rat is anyone who camps exclusively in trail shelters.
Sherp
To act as a Sherpa. "We sherped 80 pounds of gear to camp."
Sobo
South bounder (AT or PCT).
Social Trails
Unofficial shortcuts that connect individual sites to each other, restrooms, etc. at campgrounds.
Soloing
Whether hiking, backpacking or climbing, soloing is going alone. When climbing, soloing vaguely means doing any climb by yourself where injury would result in the event of a fall.
Sweeper
Last hiker in a group -- by design. Person follows all others, ensuring that no one falls behind or is left needing assistance.
Switchback
Ever been on a trail that zigzags up a mountain? That's a switchback. Makes the hike easier if not longer, and minimizes erosion problems.
Talus Slope
Loose jumbled rocks with poor or dangerous footing on the side of a mountain. A slope covered with small individual rocks. Allegedly, talus is larger than scree.
Thru-hiker
This is the opposite of a slack packer. Usually applied to someone attempting to complete the Appalachian Trail, Pacific Crest Trail, or some other lengthy trek requiring meticulous advance planning and commitment to the task at hand regardless of circumstances. (The slack packer is not meticulous and will bow out gracefully when he or she tires.) Whereas a slack packer will do day-long sessions, and a backpacker will do a few overnight sessions, a thru hiker is attempting to go start-to-finish. Thru hikers come in a variety of types; see "white-blazers," "rainbow-blazers."
Tourist
More or less the same as the regular definition, but with the added meaning of someone who blasts into a scenic area, stays at a resort property and plays lots of golf. When they do hike, they head for the busiest trail wearing the latest gear and blabbing into a cell phone. Carries a topo map on a nature loop. If they have kids, they usually throw rocks off the summit while mom or dad is oblivious. Generally expects the local populace to bow and cater to their needs since they are spending lots of cash.
Townie
Someone who lives near, and perhaps lurks about, a popular trail. Some townies help thru-hikers; others go out of their way to hassle hikers.
Trail
A route made across a wild region, over rough country, or the like, by the passage of man or animal. A trail differs from a path in that a path tends to be a convenient means of foot travel to avoid roads.
Trail Angel
A townie or other person who provides unexpected and much-appreciated assistance to a hiker.
Trail Squatter
A townie or other person who regularly camps in the same spot -- usually the best spot -- on a trail.
Trailhead
The beginning of a trail; entry point.
Trail Name
A name given to thru-hikers while on the trail. The name is intended to refer to the individual's particular style, but more often refers to some odd habit or peculiarity.
Tramper
Slack packer or hiker who continues hiking regardless of weather conditions. This term is popular in New England.
Traverse
To climb a slope diagonally rather than a more direct approach. In climbing lingo, it sometimes means going almost horizontally across a face, to obtain a better route up.
Tread
The surface portion of a trail that people way on, not including back slope, ditch, and shoulder.
Trekker
These are people who enjoy the travel and journey to remote "base camps," and do so with no intention of climbing the mountain or otherwise reaching the ultimate goal. Mt. Everest base camp is a popular destination for trekkers.
Turnpike
In hiker's lingo, a trail used by a lot of folks that goes quite directly from one place to another. In trail construction lingo, it is a trail built up above wet, boggy areas by placing stone and/or dirt over fabric with logs or rocks holding the whole shebang in place.
Understory
Forest vegetation growing under the canopy.
Universal Trail
A gentle trail with very few barriers or no barriers, providing maximum accessibility to wheelchairs.
USGS
United States Geological Survey...
Vergas
Thin, often clear coating of ice on rock.
Walk-up
A high altitude summit that requires no climbing skills to reach the top; a "class 2.0" at most. Mt. Rainier is one of the best known "walk-ups."
Water bar
Rocks, logs, or whatever angled across a trail to divert rain or melt water, to protect the trail below from excessive erosion.
White-Blazer
AT and PCT hikers who rigidly follow the trail, and if forced to detour, will retrace his steps so that every foot of the "true" trail has been covered...
Yellow-Blazing
The practice of hitch-hiking or driving somewhere to cut off part of a longer hike.
Yo-yo
Describes the concept whereby a thru-hiker gets to the end...and then turns around and hikes back to the beginning. Also used to describe hikers who hike into a site and return via the same route to their car.
Zero Day
When a thru hiker takes a day off from hiking to heal an injury, resupply, or just hang aroung town.
Zero-Mile
The spot where a measured trail begins; may or may not be the trailhead.