- 1a : a filling thread or yarn in weaving
- b : yarn used for the weft
- 2: web, fabric; also : an article of woven fabric
In weaving the weft (sometimes woof) is the term for the thread or yarn which is drawn through the warp yarns to create cloth. Warp is the lengthwise or longitudinal thread in a roll, while weft is the transverse thread. A single thread of the weft, crossing the warp, is called a pick. Terms do vary (for instance, in North America, the weft is sometimes referred to as the fill or the filling yarn).
The weft is a thread or yarn made of spun fibre. The original fibres used were wool, flax or cotton. Today, man-made fibres are often used in weaving. Because the weft does not have to be stretched on a loom in the way that the warp is, it can generally be less strong.
The weft is threaded through the warp using a "shuttle", air jets or "rapier grippers." Hand looms were the original weaver's tool, with the shuttle being threaded through alternately raised warps by hand. Inventions during the 18th century spurred the Industrial Revolution, with the "picking stick" and the "flying shuttle" (John Kay, 1733) speeding up production of cloth. The power loom patented by Edmund Cartwright in 1785 allowed sixty picks per minute.
The expression "woof and warp" (also "warp and woof", "warp and weft") is sometimes used metaphorically as one might similarly use "fabric"; e.g., "the warp and woof of a student's life" means "the fabric of a student's life." The expression is used as a metaphor for the underlying structure on which something is built.