W = Waist. A snug measurement around the natural waist, usually around the navel. This is usually much higher than a trouser waist measurement.

H = Hips. A loose measurement around the widest parts of the hips.

F = Fell. The distance between the waist and the hip measurements.

D = Drop. The length of the kilt, measured from the waist to the desired hem length (usually top of the knee).