High rise jeans are jeans that have a high rise, meaning they ride higher on the waist than normal jeans. Because of this, high rise jeans make the wearer look slimmer by pulling in the stomach and also taller by lengthening the legs.
High rise jeans are more common among women, but is growing in popularity among men as well, especially for those going for a hipster or European style look. High rise jeans can also benefit shorter guys, by helping them to look taller by elongating their legs.
Here are some examples of high rise jeans:

A standard pair of high rise jeans

A pair of high rise jeans with an urban feel

Runway models sporting high rise jeans