homonymy

Aspect of language in which, through historical accident, two or more words may sound and look alike (homonymy proper, as in a farmer's bull and a papal bull). Other types of homonymy are homophony, (as in air and heir; gilt and guilt), which may sound the same but look different, and homography (as in the wind in the trees and roads that wind) which may look the same but sound different.

Homonyms, homophones, and homographs seldom pose problems of comprehension, because they usually belong in different contexts. Even when brought into the same context for effect (‘The heir to the throne had an air of self-satisfaction’), they are entirely clear. They may, however, be used to make puns (for example, ‘a papal bull in a china shop’).