I'm taking a zero in idylwild right now so I thought I'd define some of the hiker terms that get used on the trail.
Zero day - a day where you don't hike any miles, typically spent in town, but could also be spent on the trail
Nero day- a day with only a few miles hiked
Hiker box - usually located in town near or reuspply point. Its a box full of donated items from hikers that they don't need or want to carry anymore. Can have food, gear items, toiletries, books, and random weird stuff that really makes you wonder why they packed it.
Trail name- a name given to you by other hikers on the trail. You can't name yourself, but you can sometimes veto a name given to you. Usually characterizes some defining feature about you, or an embarrassing moment you had on the trail.
Camel up - drinking as much water as you can at a water source so you don't have to carry as much in your pack to the mext source.
Cowboy camp- sleeping directly under the stars without a tent. Watch out for condensation in the morning!!
Hiker hunger- a hunger that can strike at any moment and requires massive amounts of snacking to satisfy. I've had it strike in the middle of the night
Good pitch/bad pitch - when you set up your tent or tarp you want to have a good pitch on the rain fly so that it doesn't flap in the wind or drip water on in the rain.
Trail angel - someone who helps pct hikers on he trail. They provide rides, food, restock water caches, housing, information and trail magic etc.
Trail magic - when you come across an unexpected pleasant surprise on the trail such as food, beer, cold drinks, candy bars, etc. Could be as simple as a box of snickers under a tree, or a big party with all of the above right off the trail. Huge morale boost
Base weight - the weight of your pack with all its gear in it minus food and water.
Water cache - water jugs that are carried out near the trail by trail angels. Can make the waterless stretches in the desert a little easier/safer. Always pleasant to find but depend on them as they can easily run out given the number of hikers that go through.
Dry camp - camping far away from a water source.
That's all I can think of for now but I'll put more up as I think of them.