noun
The set of lengthwise threads held under tension on a loom, through which the weft is woven. Often contrasted with 横糸 (よこいと, weft).
See also: 横糸 (よこいと)
機織りでは、まず縦糸を張ります。
In weaving, you first stretch the warp threads.
この布は縦糸に絹、横糸に綿を使ってい
This fabric uses silk for the warp and cotton for the weft.
Weft (horizontal threads) woven through the warp. 縦糸 is the lengthwise warp, while 横糸 is the crosswise weft.
Compound of 縦 (たて, 'vertical') and 糸 (いと, 'thread'). The reading たていと is a straightforward combination.