|A bucket of a type no longer seen.|
In most cases, the bucket seems to have been used in a well, and in The Knight's Tale, Chaucer writes of Arcite going "into a studie" and then being "Now up, now doun, as boket in a welle".
Such men, explains Falstaff, will be hard to hit in the field of battle.
There is an extra hint in the man's name, 'Wart', a play on the brewer's wort. Also called a sweep, some people think the French trebuchet used in this way became a tree bucket, and then just a bucket, since, after all, that was what was on the end of the sweep.
Then again, when you look at the changes that happen in our language in even one lifetime, that is surely no more than a drop in a bucket?