Let's define the terms:
- Stitching: The general act of applying stitches (loops or interloopings of thread) to fabric, using a needle and thread. It can be for joining, decorating, reinforcing, etc.
- Stitch: A single loop or an interlacing of thread(s) that forms one unit of sewing. Lockstitch (Stitch Type 301) is a common type formed by two threads (needle thread and bobbin thread) interlacing.
- Seam: A line where two or more layers of fabric (or other materials) are joined together by stitching. The primary purpose of a seam is to join pieces of fabric. A lockstitch is very commonly used to create seams.
- Seam finish: A treatment applied to the raw edges of a seam allowance to prevent fraying and improve appearance and durability (e.g., overlocking/serging, binding, pinking).
- Hem stitching (Hemming): The process of finishing the raw edge of a fabric by turning it under and stitching it down to create a hem. Hemming uses stitches, and the result is a hem, which is a type of edge finish.
The question describes "Joining two or more layers of fabric using lock stitch". This precisely defines the formation of a
seam. The lockstitch is the type of stitch used, and the result of joining fabric layers with stitches is a seam. \[ \boxed{\text{Seam}} \]