Jeans are trousers made from denim. The American blue jean was invented by Jacob Davis and Levi Strauss by 1873. The word "jeans" comes from the French phrase bleu de Gênes, literally the blue of Genoa.
Initially, jeans were simply sturdy trousers worn by workers, especially in the factories during World War II. During this period, men's jeans had the zipper down the front, whereas women's jeans had the zipper down the right side. By the 1960s, both men's and women's jeans had the zipper down the front.
Jeans (known as dungarees by then), along with light-blue stenciled cambric shirts, became part of the official working uniform of the United States Navy in the 20th century prior to being replaced by the coveralls, utilities and, more recently, the blue and gray digital-camouflaged navy working uniform. This was to prevent other more traditional uniforms from becoming soiled or torn in the ship's rugged working environment and thus leaving them for wear during ceremonial occasions.
After James Dean popularized them in the movie Rebel Without a Cause, wearing jeans by teenagers and young adults became a symbol of youth rebellion during the 1950s. Because of this, they were sometimes banned in theaters, restaurants and schools.
During the sixties the wearing of jeans became more acceptable, and by the seventies it had become general fashion in the United States, at least for casual wear.
Notably, in the mid-seventies the denim and textiles industry was revolutionized by the introduction of the stone-washing technique by GWG (Great Western Garment Co.). Denim suddenly became an attractive product for all age groups.
Acceptance of jeans continued through the eighties and nineties to the point where jeans are now a wardrobe staple, with the average North American owning seven pairs.
Jeans can be worn loosely or snugly. Historic photographs indicate that in the decades before they became a staple of fashion, jeans generally fit quite loosely, much like a pair of bib overalls without the bib. Indeed, until 1960, Levi Strauss denominated its flagship product "waist overalls" rather than "jeans".
Text courtesy of: Wikipedia. Photos courtesy of: 1. jake.umwblogs.org 2.uvm.edu 3. abundancesecrets.com 4. denimology.com 5. jeanfactory.com 6. fashioninmotion.wordpress.com