Weft

In weaving, the weft (sometimes woof) is the term for the thread or yarn which is drawn through, inserted over-and-under, the lengthwise warp yarns that are held in tension on a frame or loom 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). Each individual warp thread in a fabric is called a warp end or end.

The weft is a thread or yarn usually 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.

A useful way of remembering which is warp and which is weft is: 'one of them goes from weft to wight'.

The words woof and weft derive ultimately from the Old English word wefan, to weave. Warp means "that which is thrown away" (Old English wearp, from weorpan, to throw, cf. German werfen, Dutch werpen).

Very simple looms use a spiral warp, in which a single, very long yarn is wound around a pair of sticks or beams in a spiral pattern to make up the warp.

...
Wikipedia