noun Date: circa 1884 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
CROSSHAIR
Meaning of CROSSHAIR in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012