\Col`li*ma"tion\, n. [Cf. F. collimation, fr. a
false reading (collimare) for L. collineare to direct in a
straight line; col- + linea line. Cf. {Collineation}.]
The act of collimating; the adjustment of the line of the
sights, as the axial line of the telescope of an instrument,
into its proper position relative to the other parts of the
instrument.
{Error of collimation}, the deviation of the line collimation
   of an astronomical instrument from the position it ought
   to have with respect to the axis of motion of the
   instrument.
{Line of collimation}, the axial line of the telescope of an
   astronomical or geodetic instrument, or the line which
   passes through the optical center of the object glass and
   the intersection of the cross wires at its focus.