Simple Definition of crosshair
: a very thin wire or thread that is seen when you look into a microscope, telescope, etc., and that is used for precisely viewing or aiming at something
Full Definition of crosshair
: a fine wire or thread in the focus of the eyepiece of an optical instrument used as a reference line in the field or for marking the instrumental axis —used figuratively to describe someone or something being targeted as if through an aiming device having crosshairs <… in the crosshairs this political season — J. H. Alter>
First Known Use of crosshair
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