noun al·i·dade \ˈa-lə-ˌdād\

Definition of alidade

  1. :  a rule equipped with simple or telescopic sights and used for determination of direction: such asa :  a part of an astrolabeb :  a part of a surveying instrument consisting of the telescope and its attachments

Origin and Etymology of alidade

Middle English allidatha, from Medieval Latin alhidada, from Arabic al-ʽiḍāda the revolving radius of a circle

First Known Use: 15th century

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