What does 'Kick the bucket' mean?

To kick the bucket is an English idiom, considered a euphemistic, informal, or slang term meaning "to die". Its origin remains unclear, though there have been several theories.

A common theory is that the idiom refers to hanging, either as a method of execution or suicide. However, there is no evidence to support this. Its earliest appearance is in the Dictionary of the Vulgar Tongue (1785), where it is defined as "to die". In John Badcock's slang dictionary of 1823, the explanation is given that "One Bolsover having hung himself from a beam while standing on a pail, or bucket, kicked this vessel away in order to pry into futurity and it was all UP with him from that moment: Finis".

Yet another theory seeks to extend the saying beyond its earliest use in the 16th century with reference to the Latin proverb Capra Scyria, the goat that is said to kick over the pail after being milked (920 in Erasmus' Adagia). Thus a promising beginning is followed by a bad ending or, as Andrea Alciato phrased it in the Latin poem accompanying the drawing in his Emblemata (1524), "Because you have spoilt your fine beginnings with a shameful end and turned your service into harm, you have done what the she-goat does when she kicks the bucket that holds her milk and with her hoof squanders her own riches." Here it is the death of one's reputation that is in question.