- alidade, alidad - surveying instrument consisting of the upper movable part of a theodolite including the telescope and its attachments
--1 is a kind of surveying instrument, surveyor's instrument
--1 is a part of theodolite, transit - alidade, alidad - surveying instrument used with a plane table for drawing lines of sight on a distant object and for measuring angles
--2 is a kind of surveying instrument, surveyor's instrument