What is "double knitting"

n. (context knitting English) A form of knitting in which two fabrics (connected or not) are knitted simultaneously with two yarns on one pair of needles.

Double knitting is a form of knitting in which two fabrics are knitted simultaneously on one pair of needles. The fabrics may be inseparable, as in interlock knitted fabrics, or they can simply be two unconnected fabrics. In principle, an arbitrary number n of fabrics can be knitted simultaneously on one pair of knitting needles with n yarns, as long as one is careful.