Meaning of little bighorn

(noun) a river that flows from northern Wyoming into the Bighorn River in southern Montana; site of Custer's Last Stand

a battle in Montana near the Little Bighorn River between United States cavalry under Custer and several groups of Native Americans (1876); Custer was pursuing Sioux led by Sitting Bull; Custer underestimated the size of the Sioux forces (which were supported by Cheyenne warriors) and was killed along with all his command