Some Cushion Terminologies

Knife Edge: Cushion sewed with a single seam. See example.
Fake Box Edge: Cushion sewed with a single seam, corners are cut or pleated. Also known as French Edge. See example.
Boxed Edge: Cushion sewed with two seams, boxing on all sides. See example.
Bull Nose: Cushion sewed with no seams in front, boxing on sides and back. See example.
Ties: Matching fabric ties are inserted within the seams for securing the cushions to the furniture.
Welting: Cords are sewed within the seams to reinforce them. Also provide a cleaner look to the finished cushion. Self-welting uses the same fabric as the cushion itself to wrap around the cord. Contrasting or coordinating fabrics can also be used for wrapping the cords.
Buttons: Buttons wrapped in matching fabric are sewed onto cushions on both sides giving a tufted look to the cushion. They also help to keep the cushion filling in place.