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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.
[French, from Medieval Latin alidada, sighting rod, from Arabic al-'iḍāda, the revolving radius of a circle : al-, the + 'iḍāda, revolving radius (alternate form of 'aḍud, humerus, from 'aḍada, to lop, cut (trees); see ʕṣ́d in Semitic roots).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
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]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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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|
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