the act of checking or adjusting (by comparison with a standard) the accuracy of a measuring instrument

alter or regulate so as to achieve accuracy or conform to a standard

the act of adjusting or aligning the parts of a device in relation to each other

the accurate adjustment of the line of sight of a telescope

an adjustment of the intervals (as in tuning a keyboard instrument) so that the scale can be used to play in different keys

adjustments made to an engine to improve its performance

an adjustment that causes something to occur or recur in unison