1) Firearm component 
[firearm] Boresight is the adjustments made to an optical firearm sight or iron sights, to align the firearm barrel and sights. This method is usually used to pre-align the sights, which makes zeroing (zero drop at XX distance) much faster. A device called a bore sighter or collimator is used to accomplish this. It consists of an optical he...
A term used to describe crude adjustments made to an optical firearm sight, or iron sights, to align the firearm barrel and sights. This method is usually used to pre-align the sights, which makes zeroing (zero drop at XX distance) much faster.
the point of intersection, defined by its geographical coordinates, of the beam axis of the transmitting antenna of a broadcasting satellite and the surface of the Earth
to verify the alignment of the sights and bore of (a firearm).