Do you have a defined waist?

It is a subtraction, not a judgement

A defined waist is not a small waist. It is a waist that is smaller than what sits above and below it by a specific margin, which is why someone can have a 60cm waist and no definition, and someone else can have an 85cm waist and plenty.

There are two ways to clear the line, and either is enough. A bust minus waist of 22.9cm with the hip level does it from above. A hip minus waist of 25.4cm does it from below, and that one is larger because it is doing the job on its own rather than confirming what the bust already said.

The same 22.9cm applies again once the hip is clearly the widest point rather than level with the bust: clear it and the reading is a defined waist under a wide hip, miss it and the reading is a plain bottom-heavy frame. Two shapes, one subtraction, and the only difference is what the hip is doing.

• Bust minus waist, hip level with the bust: 22.9cm or more.
• Hip minus waist, bust and hip less than 9.2cm apart: 25.4cm or more.
• Hip minus waist, hip clearly leading the bust: 22.9cm or more.
• Waist at or above the bust: the opposite answer, and the one the classifier checks first.

What each answer changes

A defined waist is an asset in the specific sense that the rules argue hardest about not burying it. Cuts that follow the waist gain; boxy volume that runs straight past it loses, and loses more than almost anything else in the table, because it reads wider than the body underneath it.

Without definition the job reverses: the rules stop trying to show a waist and start building a shoulder line instead, because structure at the top is what gives a straight frame the taper it does not have naturally.

• A defined waist: the engine calls it an hourglass, and the rules protect the waist.
• Wider hips with a defined waist: the engine calls it a spoon, and the rules protect the waist.
• A straight up-and-down build: the engine calls it a rectangle, and the rules build a line instead.
• A fuller middle: the engine calls it an oval, and the rules build a line instead.

The reason to measure rather than look

Both errors are common and they are not symmetric in consequence. People who think they have no waist buy volume that hides one they actually have, which the rules score as the single worst move available to that shape. People who think they have one buy cuts that grip at the widest point rather than skimming past it.

Two centimetres of tape placement is enough to move a body across either line above, so treat a result within two centimetres of a threshold as a maybe rather than a verdict. The advice on both sides of the line is graded by how firmly you sit inside your label for exactly this reason.