1. A process for combining several strands of sliver, roving, or yarn in yarn manufacturing.

2. The process of twisting together two or more singles or plied yarns, i.e., plying.

3. A British term for twisting. 4. The term doubling is sometimes used in a sense opposite to singling. This is unintentional plying.

5. A yarn, considerably heavier that normal, produced by a broken end becoming attached to and twisting into another end.