There are many different kinds of jeans, but most share the same material called denim. Jeans can actually be made of any other material which is a common confusion. The word "jean" really refers to the design of the pants. The run of the mill Levi's jeans is the best example of what a jean design is. The main difference in jeans today is the cut or fit of the jeans. Companies have very many different names for the fit of their jeans but they follow some very basic principles that are not new, they simply follow changing fashion trends.

To start off there are three major sections of a pair of jeans. Where the jeans rest on a person's waist is called the rise. There are high,regular and low rise jeans depending on if the sit above, at or below the waist respectively. Next, the thigh of the jeans has three different fits as well. A full thigh is wide and very standard. A relaxed thigh is slightly loose, and a fitted thigh is the tightest. Finally there is the opening of the leg at the bottom. A tapered opening will get narrower than the thigh. Straight means that the opening will be just as wide as the thigh. A boot-fit means that it will be slightly wider than the thigh of the jeans. Finally, there is the flare which is the widest opening at the bottom. All of these can be mixed up to create a custom look by each designer.

There are also a few extra touches to jeans that refer to a purpose the jean actually serves. A carpenter jean is an old term for a loose fitting jean with a hammer loop on one side and two side pockets. There is also a utility jean that is loose fitting and has reinforced fabric on the knees.
Popular trends right now don't always name each fit in the title but will usually have a full description available somewhere. Like, a low-rise boot-fit usually means that it is a low waist, fitted thigh and a boot-fit opening. Certain cuts accentuate different body types and tastes.