Definition of Cross hair
1. Noun. Either of two fine mutually perpendicular lines that cross in the focus plane of an optical instrument and are use for sighting or calibration. "He had the target in his cross hairs"
Cross Hair Pictures
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Lexicographical Neighbors of Cross Hair
Literary usage of Cross hair
Below you will find example usage of this term as found in modern and/or classical literature:
1. The Principles and Practice of Surveying by Charles Blaney Breed, George Leonard Hosmer (1908)
"(a) To make the Horizontal Cross-Hair truly Horizontal when the ... This may be done by rotating the cross.hair ring as in the case of the transit (Art. 71, ..."
2. A Text-book of Mineralogy: With an Extended Treatise on Crystallography and by Edward Salisbury Dana, William Ebenezer Ford (1922)
"... OF THE ANGLES OÇ CRYSTALS it is bisected also by the vertical cross-hair and its angular position read by means of the graduated scale and vernier. ..."
3. Appletons' Annual Cyclopædia and Register of Important Events of the Year (1891)
"The utmost limit of accuracy ill the setting of a cross-hair on a fine ruled line is ... crosshair ..."
4. Plane Surveying: A Text-book and Pocket Manual by John Clayton Tracy (1907)
"This really moves the vertical cross-hair to the Irff, since the cross-hair ring is drawn towards the screw that is tightened (see p. ..."
5. Cyclopedia of Civil Engineering: A General Reference Work on Surveying by Frederick Eugene Turneaure, American Technical Society, American School of Correspondence (1909)
"If the transit is to be used for leveling, it is necessary that the horizontal cross-hair be in the optical center of the object glass. ..."
6. Proceedings by American Society of Civil Engineers (1905)
"The alidade is leveled and the point where the upper cross-hair strikes the ... Then elevate the telescope until the lower cross-hair intersects the point ..."