Denim is the fabric that blue jeans are made of.
Levi jeans are a brand that became so famous that instead of saying 'jeans' one could say 'Levis', just as instead of saying 'vacuum cleaner' we say 'Hoover' even if it's a different brand.
Ezra Pound was an American poet om the first half of the 20th century, and a friend of TS
Eliot. He later developed political opinions that were unpopular and was assumed to be mentally ill; perhaps he was. But his best poetry is really good.