Pyramid tents – These were actually the very first tent design. They utilize one straight pole at the center of the tent to make a pyramid shaped tent. In actual practice they are usually designed to utilize trekking poles, having no tent poles of their own. This design permits your trekking poles to operate as dual purpose items, cutting down your total weight. If you don’t hike with trekking poles, you can always construct your own poles from any material you choose. These tents often offer a lightweight advantage, but are relatively inefficient when it comes to useful space.
Avian tents – These are essentially a tarp tent, having two or more vertical poles. They create a slightly more rectangular form than a pyramid tent. They also often utilize trekking poles, however both the avian and the pyramid tent shapes are generally only used for light weather conditions, they have no floor and very little structure.
A-frame tents – Like those ancient army tents that grandpa used, they have two poles at each end of the tent forming an A shape, which are attached to the ground with stakes, making a long triangular shelter, these can be very tough structures, but they are often heavy because of their less efficient use of poles and the need for high tensile strength material, since it forms the top edge of the tent’s structure. Have a look at simple to construct for more info on this.
Modified A frames – These tents have a third pole, sometimes a hoop to open up the center area more, sometimes a cross pole, connecting A frames, making the tent freestanding. These are notable improvements in stability, but still often heavier than many options.
Hoop or Waypoint tents – These often have two hoop shaped poles that hold the body of the tent up, and using stakes they keep the structure taught and standing. The drawback of these tents is their non-freestanding nature makes them difficult to pitch at times. It also gives up some stability in behalf of shaving weight
Dome tents – These tents use crossing poles, or a hubed pole system to create a dome shape. They offer the best use of space and the strongest design. They are most commonly four season tents and can hold up in the harshest conditions, however they are also usually the heaviest, they use lots of poles and take loads of time to set up. If you are trying to choose a tent, it is important to decide just what you are planning to use it for. Choosing between the trade offs of each design is the art of making decisions about your gear.