The Hiker's Dictionary: A Glossary of The Most Important Hiking and Backpacking Terms & Acronyms (2024)

Like any serious hobby, hiking has a lot of jargon and confusing terms that can frustrate any beginner. Even if you’re trying to learn more, without “speaking the language,” it can be hard to follow conversations, articles or discussions about hiking or backpacking.

You may end up feeling like this:

That’s why I put together this handy glossary with the definition of 72 of the most common terms and acronyms you need to know. Be sure to bookmark it for future reference!

10 Essentials (or Ten Essentials)

An ever-evolving list of "essentials" that everyone should take on every hike, in case of an emergency or if they get lost and need to spend an unplanned night out. The list usually includes map and compass, sun protection (hat, sunglasses, sunscreen), extra layers, fire starting materials (lighter, matches, tinder), snacks, first aid supplies, illumination (flashlight or headlamp) and various camp tools (knife, axe, trowel). Check out my Ultimate Backpacking Checklist for a full list of overnight essentials.

100MW

The "100 Mile Wilderness" is a remote stretch of the AT in northern Maine. The 100 Mile Wilderness is known for being very remote and grueling, with limited resupply options along the way. It's on my list of best New England Hikes.

Alpine Zone

The area near the tops of tall peaks where it's too windy and the soil is too thin to allow trees or large plants to grow. The exact altitude where the alpine zone starts can vary between regions and even mountains in similar regions, due to local weather patterns. Alpine Zones are usually covered in snow fields or Talus.

AMC

The "Appalachian Mountain Club" has a huge presence in the White Mountains of New Hampshire, as well as throughout some of the more popular backcountry destinations across New England. The run a number of high-end Huts.

AT

The "Appalachian Trail," a 2,184 mile long trail between Springer Mountain in Georgia and Mount Katahdin in Maine.

Base Weight

The weight of your backpack plus all the gear that's inside it, but not counting consumables like food, water and fuel. Your Base Weight is mostly determined by your "Big 3" items: sleeping bag, backpack and shelter. Most backpackers should shoot for a Base Weight of 15-20lbs. Ultralight backpackers have a Base Weight of 10-12lbs or less.

Beta

Beta is specific, insider information about a hike, usually coming from someone who just completed it. A lot of times you can get good beta about an upcoming hike by talking to people in town or on message boards. They might tell you about specific tricky spots, shortcuts, Caches or other good-to-know information.

'biner

Short for carabiner, those metal clips that climbers use to secure rope, slings and other gear. Often used by hikers to attach things to their pack or hang things up around camp.

Bivy Sack (or Bivvy Sack)

A waterproof sack that goes over your sleeping bag to add warmth and protection from the elements. Some hikers carry them as an emergency shelter, while others hikers may use it as their primary shelter, or to add more protection and warmth to another tarp shelter.

Blaze

A colored mark, usually painted or nailed to a tree, about 4 inches tall by 2 inches wide. These are used to help guide hikers if the trail gets hard to follow or makes an abrupt turn. Some areas use color-coded systems to help hikers figure out which trail they're on.

Bluebird Day

A day marked by completely cloudless, clear blue skies. Such great weather has been known to cause a strong sense of euphoria and a hearty fist pump, especially when hiking up in Alpine Zones.

Book Time

Book Time is a reference to the estimated amount of time a hike should take, following this simple formula: 30 minutes for each mile plus 30 minutes for each 1,000 feet of elevation gain along the hike. It's the formula that the AMC and many others use to provide a ballpark estimate of a hike's duration.

Bushwhack

Bushwhacking is the process of travelling off-trail, sometimes through dense trees, branches and bushes. While trails are usually wide and clear, Bushwacking off-trail may be much slower since the hiker is required to detour around — or fight their way through — the bushes and trees in their way.

Cache

A Cache is a place where you store gear, food and other supplies before a long trip. The Cache is usually on or near the trail, allowing you to resupply when you reach it.

Cairn

A structure made of rocks used to mark a trail where trees aren't present for Blazes, like in Alpine Zones. Some are just loose piles while others are more decorative.

Camel Up

Cameling Up is a process to help you stay hydrated without needing to carry lots of heavy water bottles during your hike. When you reach a water source, you refill quickly -- usually with an inline filter like a Sawyer Mini -- and then gulp down all the water immediately before heading off down the trail again. This allows you to get the water into your system quickly while avoiding the need to carry heavy, full water bottles (~2.5 pounds per liter!) on the hike. A technique commonly used by Ultralight hikers.

Cat Hole

A small hole that you dig in order to bury poop and toilet paper. Only use Cat Holes in areas with at least 6-8" of soil and Detritus. In Alpine Zones, deserts and other areas, you may be expected to pack out your human waste in a plastic bag.

CDT

The "Continental Divide Trail," a 3,100 mile long trail, following the Continental Divide along the Rocky Mountains and traversing Montana, Idaho, Wyoming, Colorado, and New Mexico.

Col (or "Notch")

A col is the lowest point on the ridge between two peaks. Sometimes referred to as a "Notch" or "Saddle," it is the point where you stop descending one peak and start ascending the next one.

Contour Lines

Contour Lines appear on Topographic Maps and represent a line between all nearby points at the same elevation. If Contour Lines are close together in an area, that means it changes elevation quickly and is very steep. Contour lines tend to form circles around mountains (if the inner lines are higher elevation) or lakes (if the inner ones are lower elevation), and also point upstream when crossing over rivers.

Cowboy Camping

Cowboy Camping entails setting up camp the way the cowboys did out west -- under the open sky. Generally it's a sleeping bag on the ground with no tarp or tent overhead. It can be a great way to enjoy a clear, starry night, but make sure there's no rain in the forecast so you don't wake up soaking wet!

Declination (or Magnetic Declination)

Declination refers to the angle between "Magnetic North" (where your compass needle points) and "True North" (a straight line from you towards the actual North Pole). Depending on where in the world you are, these two measurements can differ by as much as 50°, so it's important to know the local Declination if you'll be taking precise bearings or doing any serious map and compass navigation.

Detritus (or Duff)

All of the leaves, pine needles, branches, sticks and other dead and decaying plant materials that cover most forest floors. In autumn when the leaves have just fallen, this can be many inches thick.

Dirtbag

An avid outdoorsman or woman who eschews the comforts of civilization in order to more fully realize their outdoor passion. Often dirty with unkempt hair and living in a vehicle, they're usually seen wearing flannel shirts and ski boots or climbing shoes.

EMS

While it might sometimes refer to "Emergency Medical Services," if someone is talking about gear that they bought at EMS, they're probably referring to "Eastern Mountain Sports," an outdoor retailer based in New England.

False Peak (or False Summit)

Depending on the shape of a mountain, you may look up the trail and think you see the peak just ahead. But once you reach that spot, you may be dismayed to see that it was just a shoulder or small bump - a False Peak - and that the real peak still likes farther up the trail.

FKT

The "Fastest Known Time" is the record for completing a section of trail (usually a Thru Hike) in the shortest possible time. There usually isn't a single authority that tracks FKT, instead it's up to the community to verify GPS data or social media posts the hiker made along the way to ensure the new record is "legit," although FKT records can still be somewhat controversial.

Ford

A Ford is a river crossing that involves getting your feet wet. If you anticipate a Ford on your trip, you'll usually bring sandals or a change of footwear to use -- never barefoot! Ideally, the water won't come much higher than your knees so that there's less risk of being swept away. Make sure you have a plan in case you lose your footing so that you and your stuff don't wash away. Trekking poles can help with stability during Fords. If the water level is very low, a Ford may turn into a simple, quick Rock Hop.

Glissade

Sliding down a snow-covered field on your rear end, like sledding without the sled. A much faster (and more fun) way to descend steep snow fields, just be careful that you can control your speed and direction so you don't slide into a tree or off a cliff.

GORP

Traditionally, Good Old Raisins and Peanuts. Some claim it's Granola, Oats, Raisins, Peanuts. Either way, it's usually a big bag full of salty and savory snacks that you eat by the handful.

GPS

The "Global Positioning System" is a constellation of satellites run by the US Military that powers everything from the turn-by-turn directions in your phone to the location tracking in your favorite navigation device.

Herd Path

An unofficial trail that's formed when a large numbers of hikers decide to all follow a similar footpath over time, similar to how game trails are formed by animals. They're usually created as hikers take a natural shortcut or easier path around some obstacle.

Hump

To begrudgingly carry an excessively heavy load. It's often the responsibility of the guide or leader of a group to carry a ton of extra group gear that they wouldn't normally take. Climbers also often have to Hump in their entire gear rack until they get to the base of their climb.

Hut

Huts can vary from dilapidated old sheds to full-service hotels. They are a permanent backcountry shelter with four walls and roof that can sleep any number of backpackers, depending on their size.

HYOH

Meaning "Hike Your Own Hike," the idea that we should all live and let live on the trail.

JMT

The "John Muir Trail" is a 210 mile trail that follows a section of the PCT. Almost entirely above 8,000 ft of elevation, much of the trail is in the Alpine Zone, with gorgeous big-mountain views and wildflowers.

Lean-to (or Leanto)

A sturdy shelter built along popular trails that consists of a raised floor, roof and three walls. They usually fit anywhere from four to a dozen backpackers. With one wall left open, lean-tos allow you to escape wind and precipitation while still performing camp chores like cooking.

LNT (or Leave No Trace)

"Leave No Trace" is a series of 7 principles designed to help backpackers and campers think about ways to minimize the impact that their presence has on the natural environment.

MEC

"Mountain Equipment Co-op" is the largest outdoor retailer in Canada. Originally catering specifically to alpine mountaineers, they've been moving to focus on a wider audience of outdoor enthusiasts.

Monorail

Monorail is the term used to describe the narrow band of snow and ice that remains down the center of a trail into late spring, even after most of the other snow has melted. It forces hikers to either walk on it like a balance beam or else forces them into the mud on either side.

NOBO

Short for "North Bound." A term used to describe Thru Hikers that start at the southern terminus of a long trail and head north.

NOLS

The "National Outdoor Leadership School" is one of the largest and most well-known outdoor education programs. They lead trips all over the world for students and adults of all ages. The also teach a number of wilderness medicine classes like WFR through their Wilderness Medicine Institute (WMI).

NPS

The National Park Service in the United States, in charge of running and protecting the National Parks.

PCT

The "Pacific Crest Trail," a 2,654 miles long trail through Washington, Oregon, and California following the highest portion of the Sierra Nevada and Cascade Range.

Peak Bagging

The process of summiting (or "bagging") a collection of related peaks in an area. It's like going through a to-do list of challenging but rewarding hikes. Popular Peak Bagging lists include the "New Hampshire 4000 Footers" (48 peaks) and the "Colorado Fourteeners" (53 peaks).

Posthole

When hiking through fresh, deep snow, Postholing is when each step you take sinks far down into the snow, sometimes burying your entire leg. Postholing is extremely tiring and slow-going. Groups of hikers will often switch up the person in the front, allowing the old leader the easier task of following in the new leader's footsteps (or Postholes).

PUD

"Pointless Ups and Downs" are areas of annoyingly rolling terrain that don't actually result in any elevation gain. Despite some trails going up and over several 30' hills in a row, that section would appear as "flat" terrain on most Topographic Maps, causing extra frustration for any unsuspecting hikers. Knowing about PUDs ahead of time requires getting good Beta.

Redline

To have "Redlined" an area means that you've hiked every single inch of trail in it, including all of the major trails as well as all of the smaller connector sections. Print out a map of the area you want to Redline and trace all the trails you've already done with a red marker. Whatever is left uncovered is where you hike next. You've completed a Redline attempt when every section of every trail is "Redlined out". It's the ultimate measure of really knowing an area like the back of your hand.

REI

One of the most popular outdoor retailers in the US, "Recreational Equipment, Inc." is a common place for first-timers to load up on camping and hiking gear.

Rock Hop

A Rock Hop is a river or stream crossing that can be done without getting your feet wet. Generally done by hopping from rock to rock through a low-running channel of water. A Rock Hop is generally faster and safer than a Ford.

SAR

Stands for "Search and Rescue," they're almost always volunteers who leave their families and careers behind when backcountry enthusiasts get themselves into trouble.

Scree

A field of loose rocks smaller than the size of your head. It can be very tricky to keep your footing in a Scree field. The small rocks will often move or slide underfoot, making it very tricky to avoid ankle or knee injuries.

Section Hike

When someone isn't able to complete a Thru Hike in one contiguous effort, they may instead choose to complete the trail over a longer period by hiking smaller sections of it and returning to society in between. A term popularized by Phillip Werner.

Slackpacking

Carrying a minimal load of food, water and gear, usually because someone else in your group is Humping everything else, or because you're planning to stay in Huts along your route.

SOBO

Short for "South Bound." A term used to describe Thru Hikers that start at the northern terminus of a long trail and head south.

Stealth Camp (or Dispersed Camp)

To setup a low-impact campsite in a more pristine nook, away from more heavily-used campsites. It can be useful to help avoid bugs, bears, mice and other creatures that have become accustomed to campers' presence in a certain area. Stealth camping is frowned upon by many since it is hard to do well and truly Leave No Trace. In popular areas, it's better to centralize the human traffic to one area to avoid leaving marks and blemishes all over the landscape.

Switchbacks

When a trail zig-zags back-and-forth up a very steep section of terrain. It adds distance to a trail but also makes it easier to hike - think of climbing straight up a ladder versus covering the same height on a very long ramp. Switchbacks also help prevent erosion on steep slopes, so be sure to follow the trail and avoid the temptation to cut straight up.

Talus

A field of larger boulders that often requires hands and feed to scramble over. Route-finding can be very slow and laborious through Talus fields. Commonly found in Alpine Zones.

The Big Three (or The Big 3)

The three most essential pieces of gear that any backpacker carries: sleeping bag, backpack and shelter. These items also tend to be the heaviest, so those looking to go Ultralight often look to these 3 items to cut the most from their Base Weight.

Thru Hike

Hiking an entire trail contiguously from end-to-end, usually at least 100 miles over more than a week. Famous Thru Hikes include the Appalachian Trail (AT) and Pacific Crest Trail (PCT).

Thru Hiker

Someone who is in the process of completing a Thru Hike. See also Dirtbag. 😉

Topo (or Topographic)

Topography focuses on the shape and features of the land — hills and valleys, rivers and lakes. A topographic map (or "Topo Map") is one that shows the natural features of a landscape, including Contour Lines of similar elevation.

Trail Angel

A local who isn't actively hiking the trail but does nice things for hikers who are. Trail Angels may run van shuttles from the trailhead into town, or leave Caches of snacks or beer along the trail.

Trail Name

Often Thru Hikers will adopt a moniker or nickname while they're on the trail. It usually has an interesting backstory and tends to be given by another Thru Hiker after a particularly memorable experience. It can be a way for the Thru Hiker to dissociate their "real" identity back home with the antics they're up to on the trail.

Trail Magic

Trail Magic is a surprise treat or Cache left on the trail for future hikers to enjoy. Sometimes they're intentionally left by Trail Angels and sometimes they're lost or discarded items that earlier hikers left behind.

Trailhead

The trailhead is the place where your hike starts or stops -- where you cross over from being in civilization to being in the backcountry. Most trailheads have a parking lot and many offer free maps or signs with information about the hikes you can access from them.

Triple Crown

The crowning accomplishment of Thru Hiking the AT, PCT. and CDT.

UL (or Ultralight)

The goal of going Ultralight is to carry a Base Weight of less than 10-12lbs. There are many reasons for going Ultralight and most of them boil down to the fact that you can hike farther, faster, and see more without getting as tired and with less chance of injury. The trade-off with carrying less gear is that you need more experience and skills (which weigh nothing).

USGS

The United States Geological Survey, an agency who produces free Topographic Maps for virtually every corner of the US.

WFA

"Wilderness First Aid" is usually a weekend-long course covering the basics of Wilderness Medicine for avid outdoorsmen and women. It covers the basics of patient assessment and how to treat and improvise solutions for basic, common medical problems.

WFR (or Woofer)

A "Wilderness First Responder" is someone who has taken a week-long class on intermediate-level Wilderness Medicine. Most mountain guides and Search and Rescue personnel are trained to Wilderness First Responder level, and I am as well. 😊

Zero Day (or Take a Zero)

A zero day is when you spend two nights in a row in the same campsite and don't do any hiking during the day. This can be used on longer Thru Hikes to help recover from injury, rest, or wait out a storm.