What’s the difference between weft and warp?

To weave fabric two groups of thread are used on the loom: that used for the weft, which threads horizontally; and that used for the warp, which weaves vertically.

These threads can be of different colours (coloured nylon thread like Tintofilo) or type of thread and it is for this reason that some fabrics may be, for example 50% wool and 50% silk.