
1) Sewing stitch
Found on
https://www.crosswordclues.com/clue/overlock

An overlock is a kind of stitch that sews over the edge of one or two pieces of cloth for edging, Hemming, or seaming. Usually an overlock sewing machine will cut the edges of the cloth as they are fed through (such machines being called `sergers` in North America), though some are made without cutters. The inclusion of automated cutters allows .....
Found on
http://en.wikipedia.org/wiki/Overlock

to oversew a hem or fabric edge to prevent fraying
Found on
http://phrontistery.info/o.html
No exact match found.