Definition
A keyhole opening is a small slit or teardrop-shaped opening at a neckline, usually at center back, closed at the top with a button and loop.
Your head is much bigger around than your neck, so a woven top or dress with a close round neckline cannot go over the head unless the opening is enlarged. A keyhole provides that extra opening without a zip: a short slit, often 8 to 12 cm (3 to 4 3/4 in) long, that opens when you pull the garment on and closes with a single button and a thread or fabric loop at the neck.
It is easier to sew than a zip and adds a neat detail at the back or front. Construction varies:
- Faced keyhole: the slit is stitched and cut through the garment and the neck facing together, then the facing is turned inside, forming a narrow teardrop.
- Back seam keyhole: the center back seam is left open at the top, the seam allowances are turned and stitched, and the neckline is finished with a facing or binding.
- Bound keyhole: a strip of bias binding finishes both the slit and the neckline in one go.
Reinforce the bottom of the slit with small stitches, since it takes strain every time you dress.
Back keyholes are common on woven tops and shift dresses, including the woven top; front keyholes are a style feature on blouses and swimwear.