Buttonhole stitch

Buttonhole stitch and the related blanket stitch are hand-sewing stitches used in tailoring, embroidery, and needle lace-making.

Buttonhole stitches catch a loop of the thread on the surface of the fabric and needle is returned to the back of the fabric at a right angle to the original start of the thread. The finished stitch in some ways resembles a letter "L" depending on the spacing of the stitches. For buttonholes the stitches are tightly packed together and for blanket edges they are more spaced out. The properties of this stitch make it ideal for preventing raveling of woven fabric.

Buttonhole stitches are structurally similar to featherstitches.

In addition to reinforcing buttonholes and preventing cut fabric from raveling, buttonhole stitches are used to make stems in crewel embroidery, to make sewn eyelets, to attach applique to ground fabric, and as couching stitches. Buttonhole stitch scallops, usually raised or padded by rows of straight or chain stitches, were a popular edging in the 19th century.

Buttonhole stitches are also used in cutwork, including Broderie Anglaise, and form the basis for many forms of needlelace.

Examples of buttonhole or blanket stitches include:

Buttonhole bars are parallel rows of thread laid across an open space in lace or cutwork and then completely covered with closely space buttonhole stitches.

Detached buttonhole stitch

Tailor's buttonhole stitch

Buttonhole stitch variations

Buttonhole shading

...
Wikipedia