Rebus

A rebus ( \ˈrē-bəs\ ) is an allusional device that uses pictures to represent words or parts of words. It was a favourite form of heraldic expression used in the Middle Ages to denote surnames.

For example, in its basic form, three salmon (fish) are used to denote the surname "Salmon". A more sophisticated example was the rebus of Bishop Walter Lyhart (d.1472) of Norwich, consisting of a stag (or hart) lying down in a conventional representation of water.