A small town in Eastern Oregon, that constantly talks crap about other towns that are better than them, which is everyone. They are especially jealous of Boardman, which has a high school called Riverside, which is three time state champs for soccer, and has really athletic guys, and can school "shumatilla" in almost everything, except being stupid.
by Bigbekay November 27, 2011
N. - The bowel movement resulting from desperately refusing to crap for many days while backpacking, being at summer camp, or otherwise lacking access to a reasonable restroom facility.
Arwen cranked out a painful Umatilla after a week, and it was fortunate that she did not need surgery.
by Les Miller September 29, 2007