• WordNet 3.6
    • n alidade surveying instrument used with a plane table for drawing lines of sight on a distant object and for measuring angles
    • n alidade surveying instrument consisting of the upper movable part of a theodolite including the telescope and its attachments
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Webster's Revised Unabridged Dictionary
    • n Alidade 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
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Century Dictionary and Cyclopedia
    • n alidade A movable arm passing over a graduated circle, and carrying a vernier or an index: an attachment of many instruments for measuring angles. See cut under sextant.
    • n alidade A straight-edge carrying a telescope: an attachment of the plane-table for transferring to paper the direction of any object from the station occupied.
    • n alidade Also written alhidade.
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Webster's Revised Unabridged Dictionary
LL. alidada, alhidada, fr. Ar. al-'idāda, a sort of rule: cf. F. alidade,


In literature:

The second lesson takes up the preparation of the stride scale on the alidade and the different kinds of maps, made in military sketching.
"Military Instructors Manual" by James P. Cole and Oliver Schoonmaker
An additional article of the sketcher's equipment is a holder for his pencils, alidade, eraser, knife, pins, etc.
"Manual of Military Training" by James A. Moss
All this required the establishment of an accurate baseline and a number of control points by means of alidade and stadia-rod measurements.
"The Cultural History of Marlborough, Virginia" by C. Malcolm Watkins