Alidade
Pronunciation : Al"i*dade
Part of Speech : n.
Etymology : [LL. alidada, alhidada, fr. Ar. al-'idada a sort of rule: cf. F. alidade.]
Definition : Defn: The portion of a graduated instrument, as a quadrant or astrolabe, carrying the sights or telescope, and showing the degrees cut off on the arc of the instrument Whewell.
Source : Webster's Unabridged Dictionary, 1913