Why do we say "It ain't over until the fat lady sings"?

Meaning:

The outcome of a contest cannot be assured until the results are in.

Background:

There is much debate about the source of this expression with some saying that it originated in the Southern USA and others that it is a sports expression from the 1970s. Wherever it originated, there seems little doubt that it gained its national popularity in the sporting arena. According to phrases.co.uk, the first known recorded use is by sports presenter Ralph Carpenter in a March 1976 broadcast:

Bill Morgan: "Hey, Ralph, this... is going to be a tight one after all."
Ralph Carpenter: Right. The opera ain't over until the fat lady sings."

Most sources assume that the fat lady refers to the Valkyrie Brunnhilde, whose ten minute solo draws the fourth of Richard Wagner's Ring Cycle operas to a close. Traditionally, the part of Brunnhilde is played by a well-padded soprano, whose appearance at the end of the 14-hour cycle must be something of a relief to even the most ardent of opera-lovers.

However, there is a hole in this theory as no one can explain why sports commentators, of all people, would be making an allusion to an operatic figure. And this is where we need to circle back to the start and look again at the claims of many in the Southern USA who say that they recollect the expression from their childhoods, long before the 1970s; for example, "church ain't out till the fat lady sings," and "it ain't over till the fat lady sings the blues."

More expressions and their source

Challenge yourself with BookBrowse Wordplays