“Break a leg” is a well-known saying in theatre which means “good luck”. It is typically said to actors before they go out onto stage to perform.
The expression reflects a theatrical superstition in which wishing a person “good luck” is considered bad luck. The expression is sometimes used outside the theatre as superstitions and customs travel through other professions and then into common use.
In the United Kingdom, the most common idea about the origin of the expression comes from tradition. Historians know from the time of King James I and Shakespeare’s King’s Men that actors would, on occasion, receive tips on top of their salaries. Rather than receiving tips directly from the company or theatre, tipping was left to the audience . During the final bows or curtain call, audiences would throw money, usually coins, onto the stage depending on how well they enjoyed the performance. In some bad performances they would throw rotten vegetables, but in the good cases, money. Actors would then ‘take a knee’, effectively breaking their leg line, on stage and pick up the money. As a result, when a person wishes someone to ‘break a leg’ it refers to wishing them success in their performance so in the end they would have to kneel down and collect a welcoming tip. Theatre evolved and the tradition of tipping changed to one of throwing flowers on stage, as well as presenting flowers.
A few others?
In traditional curtains, the legs of the curtain were constructed from long wooden rods. In the case of many encores, curtains would be lifted and dropped numerous times causing them to ‘break’.
Another popular alternative theory concerning the physical “legs”, or side curtains, of the theatre proposes that the company of actors should rush onstage through the curtains to take a considerable amount of bows, thus “breaking a leg (side curtain)” in the process.
The term ‘break a leg’ may be an abbreviation for the phrase ‘break a legend’ which roughly means ‘go get yourself out there’ or related to meaning ‘break’ (example this is your big break).