Theatrical device

Wiktionary Word definitions in Wiktionary
n. A theatrical effect in which the true meaning of a situation, or some incongruity in the plot, is understood by the audience, but not by the characters in the play.

WordNet Word definitions in WordNet
n. (theater) irony that occurs when the meaning of the situation is understood by the audience but not by the characters in the play

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun EXAMPLES FROM CORPUS ▪ It is a textbook for the study of dramatic irony in all its forms. ▪ It was above all the smile of dramatic irony , of those who have privileged information. ▪ The two basic forms of irony found in these tales are verbal irony ...