What is the term for the direction in which threads run in a piece of fabric?

The term for the direction in which threads run in a piece of fabric is referred to as the "grain of fabric." This concept is fundamental to understanding how fabric behaves and how it should be cut and sewn when creating garments or other textile items.

The grain of fabric consists of two main directions: the lengthwise direction (the selvage or finished edge of the fabric) and the crosswise direction (perpendicular to the selvage). When fabric is cut along the grain, it has a different drape and strength compared to when it is cut on the bias, which is at a 45-degree angle to the grain. Understanding grain helps in achieving the desired fit and appearance of sewn projects, as well as ensuring that fabric maintains its shape and durability through wear and washing.

In contrast, texture refers to the surface quality of the fabric, such as smoothness or roughness. Weave describes how the threads are interlaced to create the fabric, while pattern relates to the design or motifs printed or woven into the fabric. Each of these terms addresses different characteristics of fabric, but none defines the directional aspect like the grain of fabric does.