The Turkic term oğuz or oğur (in z- and r-Turkic, respectively) is a historical term for "military division, clan, or tribe" among the Turkic peoples. With the Mongol invasions of 1206–21, the Turkic khaganates were replaced by Mongol or hybrid Turco-Mongol confederations, where the corresponding military division came to be known as orda.
The 8th-century Kül Tigin stela has the earliest attestation of the term in Old Turkic epigraphy, as Toquz Oghuz "nine tribes" The term occurs in numerous proper names of tribes or confederations of the time of the Turkic migration during the early medieval period, viz.
The Old Turkic stem uq-, oq- "kin, tribe" is from a Proto-Turkic *uk. The Old Turkic word is sometimes connected with the Old Turkic word oq "arrow"; Pohl (2002) in explanation of this connection adduces the Chinese T'ang-shu chronicle, which reports that "the khan divided his realm into ten tribes. To the leader of each tribe, he sent an arrow. The name [of these ten leaders] was 'the ten she', but they were also called 'the ten arrows'." An oguz (ogur) was in origin a military division of a Nomadic empire, and only secondarily acquired tribal or ethnic connotations, by processes of ethnogenesis.