GRAIN
The direction in which the threads composing the fabric run. Every woven fabric consists of crosswise threads worked under and over the more sturdy lengthwise threads.

SELVAGE
The narrow, flat, woven border resulting at both lengthwise sides when the crosswise threads reverse direction.

LENGTHWISE GRAIN
The direction of the lengthwise threads running parallel to the selvage.

CROSSWISE GRAIN
The direction of the crosswise threads running from selvage to selvage at right angles to the lengthwise threads.

BIAS
A term used to describe direction on woven fabric.
Bias is any diagonal intersecting the lengthwise and crosswise threads.
Fabric cut on the bias grain possesses much greater elasticity than cut on the crosswise grain.

TRUE BIAS
Maximum stretchability occurs on the true bias.
True bias exists at any 45 degree angle to any straight edge of a fabric whose lengthwise and crosswise threads are perpendicular.