- two fine mutually perpendicular lines or wires that cross in the focal plane of a theodolite, gunsight, or other optical instrument and are used to define the line of sight
Also called: cross wires
WordReference Random House Unabridged Dictionary of American English © 2020
- OpticsAlso called cross wires. fine wires or fibers, strands of spider web, or the like, crossing in a focal plane of an optical instrument to center a target or object or to define a line of sight.
- Printingmarks for aiding in the positioning of overlaying images for correct registration in printing. Cf. register (def. 11b).
Collins Concise English Dictionary © HarperCollins Publishers::
cross hairs pl n