An encore is the extra song or two an artist performs after appearing to end the concert, once the audience has clapped, stamped and shouted long enough. In big pop shows it is often planned in advance, which makes the dramatic exit a polite piece of theatre that everyone agrees to believe.
The word is French for again, yet in France audiences call for a repeat by shouting bis. English borrowed encore for the purpose early in the 18th century, with an early recorded use in The Spectator in 1712. Milan has its own story. Arturo Toscanini banned encores at La Scala in 1921 to protect the flow of the opera, and the rule held for decades until February 2007, when the tenor Juan Diego Flórez repeated the aria famous for its run of high Cs in Donizetti’s La Fille du régiment, the first solo encore there since 1933.