Ease (patterning) –
Ease is the difference between the body measurements the pattern is drafted for and the finished garment measurements.
Wearing Ease is the additional space added over body measurements to account for sitting, breathing, eating, and moving.
Design Ease is the additional space added over wearing ease to create a style or shape.
Negative Ease is when a pattern is drafted smaller than body measurements. This is used for stretch and knit fabrics. The amount of negative ease is determined by the stretch percentage of the fabric.