Definition of "backsight" [back•sight]

• The rear sight of a firearm. (noun)
• A measurement or reading taken back towards a point of known elevation, used to calculate the height of the theodolite. (noun)
• A measurement of a previously shot point, used to set the angle to zero when occupying a new position. (noun)
• To shoot a backsight. (verb)

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• "The swan-neck cock made a slight creaking noise as it compressed the mainspring, then there was a click as the pawl took the strain and Hagman hinged the backsight up as high as it would go, then lined its notch with the blade-sight dovetailed at the muzzle."
• "Sharpe aimed through the bars of the balcony's balustrade, lining the notch in the rifle's backsight and the leaf of the foresight on Aksel Bang's face."
• "Both a foresight and backsight are taken on the point."