proportion

In art, the size, location, or amount of one part or thing compared to another. Some subjects are governed by certain regular proportions. For instance a face consists of a rough oval; the eyes are set half way down the oval on a line that is ‘five eyes’ in width; the eyebrows arc over the whole eye; the bottom of the nose is usually as wide as the gap between the inner corners of the eyes; the mouth lies half way between the end of the nose and the chin, and at rest is as wide as the distance between the pupils of the eyes; the ears stretch from eye-level to just below the nose; and the neck starts from below the ears and gently curves towards the shoulders.