An ironic or non-literal saying of uncertain origin (a dead metaphor),[1] "break a leg" is commonly said to actors and musicians before they go on stage to perform or before an audition.
Though a similar and potentially related term exists in German without theatrical associations, the English expression with the luck-based meaning is first attributed in the theatre in the 1930s or possibly 1920s.
[2][3] The urbane Irish nationalist Robert Wilson Lynd published an article, "A Defence of Superstition", in the October 1921 edition of the New Statesman, a British liberal political and cultural magazine, that provides one of the earliest mentions of this usage in English: The stage is perhaps the most superstitious institution in England, after the racecourse.
"[4] Thus, Lynd describes the expression as existing in horse racing, though in the very middle of a paragraph that goes on to discuss the theatre and theatrical superstitions.
[5] The American playwright Bernard Sobel's 1948 The Theatre Handbook and Digest of Plays describes the theatrical superstition that "before a performance actors never wish each other good luck, but say 'I hope you break a leg.
[13] A phrase with a similar meaning appears in the German language by World War I or, at the latest, World War II, during the early days of aviation: Hals- und Beinbruch, literally "neck and leg(bone) break" or, essentially, "may you break your neck and leg".
[14] The English-language adoption of this term is plausibly explained by German-speaking Jewish immigrants entering the American entertainment industry after the First World War.
[25] There is an older, likely unrelated meaning of "break a leg" going back to the 17th and 18th centuries that refers to having "a bastard / natural child".
[26] Professional dancers do not wish each other good luck by saying "break a leg;" instead they exclaim merde, the French word for "shit".
A quick look to the street in front of the venue would tell if the play was successful: a lot of horse dung would mean many carriages had stopped to drop off spectators.
From Rotwelsch tof, from Yiddish tov ("good", derived from the Hebrew טוב and with phonetic similarities to the Old German word for "Devil").
[30] An alternate operatic good luck charm, originating from Italy, is the phrase In bocca al lupo!