If someone has “got you over a barrel,” it implies they’re in control and you’re not. People rescued from near-drownings used to be draped a barrel while the water was cleared from their lungs. However, in the more sinister situations which likely inspired the term, people were put over barrels and tied in this position to receive beatings.
Since booze often used to be shipped in barrels, “barrel fever” can be sickness from excessive drinking, a hangover, or in the longer term, the physical debilitation which often comes with chronic drinking.
The shipping of booze in barrels gave the early oil industry the idea for shipping their liquid in this standardized unit. A standard oil barrel was made 42 gallons, 2 gallons more than a whiskey barrel to cover spillage and evaporation in transport. Though most modern oil never sees the inside of a barrel, this standardized unit remains worldwide
Food was also traditionally stored in barrels, so when you were running out and had to take the leftovers and remains on the very bottom, you were “scraping the bottom of the barrel.”
Perhaps you’ve recklessly gone barrelling down the highway in your car, but this term likely comes from the wooden vehicle. Back when barrels were common in households and farms, thrill-seeking youngsters would climb in and roll down hills. You cannot steer nor stop the average barrel from inside, so this pastime was rather dangerous.
The surname “Cooper” originally meant a person in the business of making and fixing barrels, buckets, and casks. It is now a common first name.
The long tube of a gun or cannon which ammunition travels through is called a “barrel” because these tubes were either designed from or had an appearance like actual barrels in early weapons.