Harem pants are a style of pant which has a long crotch and wide ballooning legs. Traditionally they are tight only at the ankle and made in lightweigh fabrics.
Parachute pants, which were made popular by M.C. Hammer in the 80s, are a modified version of a harem pant. They have a low crotch, but instead of the leg staying the same width all the way down, they begin to taper at the knee, becoming narrow at the ankle.