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".
The theory favoured by the OED relates to the alternative definition of a bucket as a beam or yoke that can be used to hang or carry things on. The "bucket" may refer to the beam on which slaughtered pigs are suspended. The animals may struggle on the bucket, hence the expression. The word "bucket" still can be used today to refer to such a beam in the Norfolk dialect. It is thought that this definition came from the French word trébuchet or buque, meaning balance.William Shakespeare used the word in this sense in his play Henry IV Part II where he says:
Swifter than he that on the Brewers Bucket.
A third theory suggests that the origin of the phrase comes from the Catholic custom of holy-water buckets:
After death, when a body had been laid out ... the holy-water bucket was brought from the church and put at the feet of the corpse. When friends came to pray... they would sprinkle the body with holy water ... it is easy to see how such a saying as "kicking the bucket " came about. Many other explanations of this saying have been given by persons who are unacquainted with Catholic custom