Buttonhole (noun)

1. A small hole in a garment, through which a button is passed to fasten the garment.
2. A small hole in a flower, through which a button or ribbon is passed to fasten the flower to a garment or accessory.

Origin:

From button (a small fastener) + hole (an opening).

Examples:

1. He fumbled with the buttonholes as he tried to fasten his shirt.
2. She sewed buttonholes in the dress so that it could be fastened.
3. The buttonholes on the shirt were too small for the buttons.
4. He added a buttonhole to his lapel and wore a flower in it.
5. The buttonhole is an essential feature in any garment that uses buttons as fasteners.