color by number

• color by numbers

color by number (plural color by numbers)

1. (chiefly attributive) A simple coloring exercise, intended especially for children, consisting of a line drawing that divides the artwork into distinct spaces, the intended color of each indicated by a number and referenced from a key.
2. (uncountable) A technique that applies such exercises, as formerly used in the production of large-scale animations for instance.

color by number (third-person singular simple present colors by number, present participle coloring by number, simple past and past participle colored by number)

1. To complete such an exercise; to carry out such a technique by filling in each space with the appropriate color.

• paint by numbers