Often mistaken for tall or petite, length is all about the actual length of the jacket: long, medium or short. The length of jacket you prefer is directly related to the fit and style you are looking for.
Long jackets fall into two categories. For casual jackets they are typically mid thigh to knee length for comfort and warmth. For active jackets they will typically be 3-5 inches longer in the body than a medium length jacket.
Medium jackets are the most traditional fit. Medium length jackets stop at the hips or slightly below.
Short length jackets end just above the hip, giving a more tailored and fitted look.