What technique involves making triangular cuts in the seam allowance without cutting through the stitching?

The technique that involves making triangular cuts in the seam allowance without cutting through the stitching is known as notching. This method is primarily used to reduce bulk in curved seams, allowing the fabric to lay flat when turned right side out. By creating triangular cuts, you modify the fabric's shape without compromising the integrity of the seam itself. Notching helps prevent puckering and allows for smoother curves, which is especially important in garment construction where aesthetics and fit are crucial.

In contrast, clipping generally refers to making straight cuts into the seam allowance, which is also used to reduce bulk but is not the triangular cut that notching involves. Seaming pertains to the act of joining two pieces of fabric together along a seam line. Felling is a sewing technique used to finish the edges of fabric, typically to prevent fraying and provide a clean look, but does not involve the specific action of making triangular cuts in the seam allowance. Thus, notching is the correct technique for this particular question based on its unique characteristics and function in sewing.