Opening for button to go through in order to secure the garment. Generally classified as a bound (with edges finished with stitched-on fabric or leather binding) or a worked buttonhole (finished by hand by embroidering with buttonhole stitch or with similar stitching done by a sewing machine).
FDF, 1988
Context:
Handworked buttonhole, reinforced with gimp, for a crisp edge, are a hallmark of custom tailoring. Machine buttonholes work as well, but are not nearly as beautiful.