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Related to alidade: telescopic alidade
al·i·dade(ăl′ĭ-dād′) also al·i·dad (-dăd′)
1. An indicator or a sighting apparatus on a plane table, used in angular measurement.
2. A topographic surveying and mapping instrument used for determining directions, consisting of a telescope and attached parts.
1. (Surveying) a surveying instrument used in plane-tabling for drawing lines of sight on a distant object and taking angular measurements
2. (Surveying) the upper rotatable part of a theodolite, including the telescope and its attachments
[C15: from French, from Medieval Latin allidada, from Arabic al-'idāda the revolving radius of a circle]
1. a straightedge with a telescopic sight, used on a plane table for topographic surveying.
2. the entire upper part of a theodolite or transit.
[1400–50; late Middle English allydatha < Old Spanish alhidada < Medieval Latin < Arabic al-‘iḍādah the turning radius (like a clock hand) of a circle]
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|Noun||1.||alidade - surveying instrument consisting of the upper movable part of a theodolite including the telescope and its attachments|
|2.||alidade - surveying instrument used with a plane table for drawing lines of sight on a distant object and for measuring angles|