Cayuse
noun
Cay·use ˈkī-ˌyüs 
kī-ˈyüs
kī-ˈyüs plural Cayuse or Cayuses
1
: a member of a once-nomadic Indigenous people of the northwestern U.S. located primarily in eastern Oregon and Washington
Note: The Cayuse now exist as part of the Confederated Tribes of the Umatilla Indian Reservation in northeastern Oregon.
2
cayuse, plural cayuses, Western US : a native range horse
Word History
Etymology
origin unknown
First Known Use
1825, in the meaning defined at sense 1