Carding
The step that opens and aligns staple fibre into a web before bonding.
Carding
Carding combs the opened fibre into a fleece in which the fibres lie roughly parallel. That alignment is why a nonwoven has a direction: it is stronger along the machine direction than across it, and it folds more cleanly one way than the other.
For a buyer this matters at the point of conversion — where a towel is folded or cut — and it is the reason fold direction is worth discussing with the supplier rather than leaving to the converter.