Lituus
Pronunciation : Lit"u*us
Part of Speech : n.;
Etymology : [L.]
Definition : 1. (Rom. Antig.) (a) A curved staff used by the augurs in quartering the heavens. (b) An instrument of martial music; a kind of trumpet of a somewhat curved form and shrill note.
2. (Math.)
Defn: A spiral whose polar equation is r2th = 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.
pl. Litui.
Source : Webster's Unabridged Dictionary, 1913