What's the difference between drum and barrel?

Just my impression (I'm way out of date on this.) In my experience, industrial products, especially lubricants, were purchased in 55-gal. steel drums - sometimes 30-gal. These were cylindrical, with two ridges formed into the circumference for reinforcement.

I think of barrels as wooden, assembled from curved "staves," giving the barrel a "bulging" shape. I think of Budweiser being "beechwood aged" in such barrels. The famous polka, "Roll Out the Barrel" refers to a barrel of beer being rolled across the floor at a dance.

Going back even before my time, some food items such as pickles were sold in bulk from barrels in the store. You still hear the expression, "cash on the barrel head."

Of course these days the most famous barrel is a barrel of oil, which is actually just a unit of measure.

Everything is now made of plastic, as your referenced pictures show.

Best wishes, - A.

I believe this is a drum then. Avangi, are those the two ridges you are talking about? By the way, is groove the opposite of ridge?
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Sure looks like a drum to me, but the distinction is becoming blurred, I believe. Affirmative on the ridges and grooves.
Thanks, Avangi!
BTW, a barrel of oil is 42 US gallons, or about 35 imperial gallons.
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> I think of barrels as wooden, assembled from curved "staves," giving the barrel a "bulging" shape.
I agree with Avangi on this one
Barrel is s measuement (approx. 119.3 liters). The Word for the wooden container in question is 'cask'. (Just saw a documentary about the last Master Cooper (cask maker) in Britain.😎)