Over-the-knee socks

Above the knee, where nothing natural holds a sock.

An over-the-knee sock finishes on the lower thigh. Past the knee the leg stops tapering and starts widening again, so gravity works against the sock and there is no calf shape left to sit on.

Everything about the construction answers that. The leg is knitted with graduated elastane that increases toward the top, and the knee itself is shaped rather than knitted straight through, so the sock bends without pooling behind the joint.

Thigh grading. The top opening has to be graded on thigh circumference. Grading it on shoe size, which works well enough up to the knee, produces a sock that either will not go on or will not stay on.

Silicone top band, or not. A silicone band holds reliably and is visible through thin fabric. Graduated elastane alone is invisible and gentler, but needs a more accurate thigh measurement to work.

Opacity. Over-the-knee socks are often worn with skirts, so the yarn is judged on how it looks stretched, not flat. A colour that reads solid on the calf can go translucent on the thigh.

Knee shaping. Say whether the knee should be shaped. Unshaped is cheaper and perfectly acceptable in a thick winter sock; in a fine one it wrinkles behind the joint.