D defs.my
Entry 2 senses Webster, 1913

Lituus

· Lit·u·us · IPA /ˈlɪtju.əs/
01 n. A curved staff used by the augurs in quartering the heavens.
pl. Litui ((#))
  1. 1.
    A curved staff used by the augurs in quartering the heavens.(Rom. Antig.)
  2. 2.
    A spiral whose polar equation is r2θ = a; that is, a curve the square of whose radius vector varies inversely as the angle which the radius vector makes with a given line.(Math.)