What is "lockstitch"

n. (context sewing English) A stitch made by a sewing machine in which two threads are interlocked. vb. (context sewing English) To use this kind of stitch.

n. machine stitch in which the top thread interlocks with the bobbin thread

A lockstitch is the most common mechanical stitch made by a sewing machine. The term "single needle stitching", often found on dress shirt labels, refers to lockstitch.