Definition of "jeans"

As a general thing, they were dressed in homespun “jeans,” blue or yellow—there were no other varieties of it; all wore one suspender and sometimes two—yarn ones knitted at home,—some wore vests, but few wore coats.

1873, Mark Twain [pseudonym; Samuel Langhorne Clemens], Charles Dudley Warner, The Gilded Age: A Tale of To-day, Hartford, Conn.: American Publishing Company, published 1874, page 19

Think of banking today and the image is of grey-suited men in towering skyscrapers. Its future, however, is being shaped in converted warehouses and funky offices in San Francisco, New York and London, where bright young things in jeans and T-shirts huddle around laptops, sipping lattes or munching on free food.

2013 August 3, “Revenge of the nerds”, in The Economist, volume 408, number 8847