fullness

The linear amount of fabric used to create a curtain or garment.
A ten foot wide curtain with 0% fullness (aka flatsewn) would use 10' of goods.
A ten foot wide curtain with 50% fullness would use 15' of goods. Used for most theatrical draperies.
A ten foot wide curtain with 100% fullness would use 20' of goods. Because of cost and weight, usually reserved only for main curtains and travelers.

See http://www.rosebrand.com/fabric-stag...ss.aspx?rl=tnd for a good demonstration.