Known Size or Scale - Known size or scale is a depth cue that reveals depth through associations of figures and shapes that have an intrinsic size. A viewer knows that a house is larger than a mosquito so that if the two were approximately the same scale in an image, the house would be perceived as further away.
Even though the two figures are approximately the same size, the assumption is made that the duck is closer to the viewer than the elephant (as opposed to a giant duck or a miniature elephant).
Katsushika Hokusai, The Great Wave Off Kanagawa. 1823-29, color wookcut
(known size of a wave, boats, and the mountain - the assumption is that the mountain is far away rather than a tiny mountain)
Master Concepts List - alphabetical glossary
Master Concepts List - grouped by category/course