tueor.

Uncertain. De Vaan and Rix both postulate a root of the shape *tewH-. However, De Vaan suggests that the original meaning of the term was "to protect," which evolved into the meaning "to look." If this theory is accepted, then a connection with the root *tewh₂- (“to be strong”) becomes tenable. In either case, according to De Vaan, the term may derive from a Proto-Indo-European causative *towH-éye- or *towh₂-éye-. This verb would become Proto-Italic *tawe-, which may have developed into tueor via the reintroduction of -ow-. Alternatively, De Vaan postulates that *tetówh₂e, the stative form of the root *tewh₂-, could have produced the Latin verb via the same reintroduction of -ow-. Rix alternatively postulates an original Proto-Indo-European verb *tuH(h₁)yéti, which he considers to be a possible source of the Latin verb. Mallory suggests a possible derivation from a root of the shape *tew- (“to look upon favorably”). Compare typologically Russian пригля́дывать (prigljádyvatʹ) (< гляде́ть (gljadétʹ)), присма́тривать (prismátrivatʹ) (< смотре́ть (smotrétʹ)), призре́ть (prizrétʹ) (akin to взор (vzor)).