n., pl., Umatilla, or -las.
- A Native American people of northeast Oregon.
- A member of this people.
- The dialect of Sahaptin spoken by the Umatilla.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.