DC stands for double crochet. It is a crochet technique sometimes used in knitting patterns and just requires a crochet hook.
YOH once, insert hook in stitch; YOH and pull through stitch (3 loops now on hook), *YOH and pull through 2 loops on hook; repeat from * once more.
See also: sc, dc, tc, hdc, YOH, chain, join (crochet), join chain (crochet), crochet CO
