The term, of course, means “do well” or “have a great show” and is typically used before a stage performance, a show, or an audition. (I have never heard it used before filming a movie on any of the movies I’ve been involved with, but I guess it can be used in that sense too). But I’m sure you’re more interested in the origin of “break a leg”.
Like many popular sayings and terms, the origin of “break a leg” is nebulous and disputed. The term “break a leg” was used originally, many say, to discourage evil spirits from deliberately causing one’s performance to suffer. According to this theory, wishing someone “good luck” would be invoking the “evil eye”. So “good luck” would actually cause bad luck for the actor. Thus, “break a leg”, by this logic, would be a wish for good luck.
This is in line with the first documented instance of someone saying “break a leg” in terms of wishing them luck. In an October 1, 1921 edition of the New Statesman, Robert Wilson Lynd is talking about it being unlucky in horse racing to wish someone luck so “you should say something insulting such as, ‘May you break your leg!” He also mentions that theater people are the second most superstitious group next to those involved in horse racing.
Another of the early documented references of “break a leg”, this time directly referring to theater, was in the 1939 A Peculiar Treasure by Edna Ferber, where she implies a different motive, “…and all the understudies sitting in the back row politely wishing the various principals would break a leg”. Thus, they say it hoping the principal actors will break their leg so the understudies can possibly take the lead.
Another possible construction is the German phrase “Hans un beinbruch”. The sentiment here is “Happy landings” in English. Both English and German pilots use the term, but the literal translation is “breaking all one’s bones”. It is possible actors adopted this phrase, as it was just after WWI that the “break a leg” sentiment seems to have gained widespread popularity.
The term “break a leg” may be traced back to the Elizabethan language. To “break a leg”, in Shakespeare’s time, meant, literally, to bow- by bending at the knee. Since a successful actor would “break a leg” onstage and receive applause, the phrase would, in effect, be a wish for good luck. However, in the 16th century “break a leg” also meant to give birth to an illegitimate child, which is hard to connect to the theatrical world.
Others trace “break a leg” to the tradition of audiences in Ancient Greece. Instead of applauding actors, audiences would stomp their feet. Stomping to the point of actually breaking a leg is unlikely- but still, the phrase may be figurative and not literal.
An interesting historical theory attributes “break a leg” to the assassination of Abraham Lincoln. This theory traces the term to the great 19th century actor, John Wilkes Booth, who, of course, shot President Lincoln at Ford’s Theater in 1865. After Booth shot the President, he jumped from Lincoln’s upper box seat onto the stage, where he literally “broke his leg”. (Some also present this as a possibly origin of the popular phrase comedians and comics use for a successful show: “I killed them.” / “I killed the audience.”)
Landing a role in show business is called “getting a break” and being newly successful is called “breaking into the business”. These also may be where the “break a leg” term evolves from.
So as you can see here, the exact origin of “break a leg” for wishing someone luck is murky at best. But whatever first spawned the exact phrase, it seems plausible enough that it either grew in popularity from the idea of wishing bad luck on someone so that they’ll in turn be given good luck, as the early documented references of the phrase imply, or in sarcastically wishing them bad luck so that the understudy could perhaps take over the role of one of the principals if the principal actually broke their leg.
- Ballet dancers have their own version of “break a leg” which connects to the superstitious concept of not wishing other dancers “good luck”. They will say “Merde!” This translates in English to a well-known four-letter word that describes human waste. This term seems more expressive of not evoking ill or bad luck, but as well may imply feelings related to stage fright or anxiety before a performance.