First of all, there's no such thing as a dumb question. No one knows everything, although I've met a few people who thought they did, ha ha. Everyone of us had to start somewhere. I've learned a tremendous amount from Doug Ritter, and am very grateful to him for this.
Fresnel lens- Fresnel (pronounced Fruh Nell or Frah Nell) is the last name of the French scientist who invented it. Basically it is a flat lens. Since it is flat it can be made of plastic, and the plastic ones are very compact and weigh almost nothing. This site can explain it better than I can:
http://www.howstuffworks.com/question244.htmI carry a credit card sized (about 50 by 85 mm) plastic fresnel lens in my wallet. I also carry one in a backpack that is the size of a sheet of typing paper.
I assume you are familiar with starting a fire using a magnifying lens to concentrate the sun's rays onto a handful of dried grass, etc. Believe me, the big lens gets a fire going quick.
By the way, I did not know what a fresnel lenses until I read about them here at equipped.
Nalgene bottles- Nalgene is the name of a company that makes plastic products, therefore the water bottles they make are often called Nalgene bottles. They are very high quality but expensive:
http://www.nalgene-outdoor.com/So many people use Nalgene bottles that several of the backpacking type water filters are designed to be used with a Nalgene bottle. These filters have a screw on lid that fits the bottle. With this lid in place, you don't have to hold the bottle and can use both hands to operate the filter. I keep a Nalgene bottle with my PUR filter just for this purpose, but usually carry water in the 1 and 1.5 liter plastic bottles that bottled water is sold in.
Stropping- straight razors, which everyone used before disposable razor blades were invented, were stropped between each use. The razor was stroked back and forth across a heavy leather strap that was made for that purpose. This helped keep the blade sharp between sessions with the sharpening stone. This leather strap is called a razor strop or just a strop, and the act of using it is called stropping.
According to my dictionary, the word strop is a variation on the word strap. I heard that a razor strop was handy for punishing children. Lucky for me, my dad didn't own one, but he had a leather belt that worked just fine.
Anyway, some people use a strop on their knives. Here's one site with more information. A search on "leather strop" or "razor strop" should lead you to more:
http://www.premiumknives.com/Premium_Knives_help-Straight_Razor_Care.htmHope this helps!
Bill