Understanding sewing terms for either getting your lingerie made by a factory or simply to understand how you want to make your lingerie. The "How to write a Bra and Brief Tech Pack" covers the descriptions of the common sewing procedures.
So for example SN is single needle which is your regular straight stitch. Securing OL : overlocking is usually done by a Bra tack (a group of closely sewn stitching - sewn back and forth from side to side with a zigzag stitch).
Below is an extract from the booklet