a kind of ornamental hand stitching in which each stitch forms a loop through the forward end of the next.
2.
a basic crochet stitch in which yarn is pulled with the crochet hook through a loop on the hook to form a continuous strand of interlocking single loops.
3.
a machine stitch forming a chain on the underside of the fabric.
Origin
1590-1600
British Dictionary definitions for chain stitch
chain stitch
noun
1.
an ornamental looped embroidery stitch resembling the links of a chain