The combination of jeans, a button-up shirt, and a blazer. Similar to a Canadian tuxedo, accept when you wear it you look less like a bumpkin & slightly more sophisticated. The Oregon tuxedo is a classy-casual look (or smart-casual), not good enough for a black tie occasion, but it is good enough for many job interviews, giving speeches, almost any restaurant, certain business dealings, and many other occasions.
Some say the Oregon Tuxedo is a look made popular by former Oregon Governor John Kitzhaber.