Definition of "cross-staff" []

• An early navigational instrument, consisting of a wooden rod with a sliding crosspiece, used for measuring the altitude of a star; it developed into the sextant (noun)
• A surveyor's instrument for measuring offsets. (noun)

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• "To that end, its most useful instrument was not a ship or cross-staff or astrolabe, but a printing press."
• "It is hard to know how accurate these could have been, though Chinese navigators, like the Arabs, corrected their compass readings by celestial observation, using the cross-staff or the kamal."
• "[3367] Mr. Edmund Gunter, which will perform that by addition and subtraction only, which heretofore Regiomontanus's tables did by multiplication and division, or those elaborate conclusions of his [3368] sector, quadrant, and cross-staff."