It's not over until the fat lady sings or it ain't over until the fat lady sings is a saying and idiom that means that you should not presume to know the outcome of an event which is still in progress.
Or more specifically it ain't over until the fat lady sings phrase is used when a situation is nearing its conclusion.
The saying or phrase it ain't over until the fat lady sings refers to the ladies that sang in opera that were originally fat that would sing opera at the end of the opera show.
Not all opera singers are fat but in years past a fat lady would sing at the end of the opera which is where the saying of the fat lady sings came from.
Opera!
When you hear this five letter word, you probably think of a theatrical performance with lots of singing and music.
However, what about opera singers themselves?
When some people picture them, they might think of a stereotypical fat lady who wears a horned helmet.
Why is that?
One reason could be because of how opera singers were portrayed in forms of media we watched growing up. For example, in certain cartoons, an opera singer might be represented as an overweight lady with a horned helmet.
This kind of imagery can then stick with us as we grow older.
This specific representation of the “fat lady” with the horned helmet is believed to be based on Richard Wagner’s “Brunhilde” from the Ring Cycle.