[ al-i-deyd ]
/ ˈæl ɪˌdeɪd /

noun Surveying.

(in plane-tabling) a straightedge having a telescopic sight or other means of sighting parallel to the straightedge.
the entire upper part of a theodolite or transit, including the telescope, its supports, the level vials, the circle-reading device, and the spindle.



"The Handmaid's Tale" was required reading for many of us in school. Everyone else has probably watched the very popular and addictive TV show. Do you remember this vocabulary from the book, and do you know what these terms mean?
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Also al·i·dad [al-i-dad] /ˈæl ɪˌdæd/.

Origin of alidade

1400–50; variant of alhidade < Medieval Latin alhidada < Arabic al-ʿiḍādah the turning radius (like a clock hand) of a circle; replacing late Middle English allydatha (< Old Spanish alhidada) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for alidade

  • Your scale is ready to be pasted or transferred to the alidade and each 6.8.

    Military Instructors Manual|James P. Cole and Oliver Schoonmaker
  • The alidade is a triangular ruler with one or more working scales on it beside other measurements.

    Military Instructors Manual|James P. Cole and Oliver Schoonmaker
  • Close by stood an alidade, an instrument for measuring angles.

    Historical Miniatures|August Strindberg
  • After he had placed the plane table on a tripod and upon this the alidade, he started to work.

    On the Seaboard|August Strindberg

British Dictionary definitions for alidade


alidad (ˈælɪˌdæd)

/ (ˈælɪˌdeɪd) /


a surveying instrument used in plane-tabling for drawing lines of sight on a distant object and taking angular measurements
the upper rotatable part of a theodolite, including the telescope and its attachments

Word Origin for alidade

C15: from French, from Medieval Latin allidada, from Arabic al-'idāda the revolving radius of a circle
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012