At a given point, the angle between magnetic north and true north.
At a given point, the angle between the line connecting this point with the geographical center of the earth and the equatorial plane.
A refusal.
(grammar) Declension.
The act or state of bending downward; inclination.
declination of the head
The act or state of falling off or declining from excellence or perfection; deterioration; decay; decline.
Deviation.