Where did the expression 'It ain't over til' the fat lady sings' originate?

Answer 1

Women in the Opera are usually bulkier, as they have wider vocal range, and can sing louder. When they say 'It isn't over until the fat lady sings', they are referring to the last note. Traditionally in an opera, the very last note, or the finale is sung by a women, and it is either quite loud, or loud and high. Now you can see the combination of bulky women with the ending of the opera, or anything else.

More specifically, the Fat Lady is likely to be Brunhilde, who sings the final aria in Gotterdemerung, Wagners last opera in the Ring cycle. Brunhilde is usually seen as a Viking warrior with winged helmet and spear and has a suitable stature, i.e. impressive, large.....or Fat!

When she stops singing ( apart from a one-liner from someone else) its over.

(Add on:) It seems to me that I remember seeing a short film (much like "The Little Rascals") where two boys are watching an opera from the balcony. The older boy brought the younger. The younger boy starts to applaud toward the end, but the older boy (who has seen this before) says "It's not over till the fat lady sings". He then points to a Brunhilde character who definitely fits the description. I hope that someone else has seen the clip.

The phrase originates from sailors on shore leave in days gone by. Steam was the agent of propulsion, and the boiler was affectionately known as the "fat lady". The boiler had to be stoked to build up a head of steam for the ship to leave port. When sufficient pressure had been generated the whistle blew. The "fat lady" had thus sung, to signal to the sailors that their run ashore had ended.