Shed
The gap between the raised and lowered warp threads, through which the shuttle carries the weft.
Also: the shed
When some warp threads are lifted by the heddles and others stay down, a wedge-shaped opening appears between the two layers. This opening is the shed. The weaver sends the shuttle through it from one side to the other, which lays down one weft thread. Then the heddles change, the threads that were up go down and the others rise, a new shed opens, and the shuttle comes back. The order in which warp threads rise and fall from one shed to the next is what decides whether the cloth is plain, twill, satin or patterned.