declination

noun8

1. •
   At a given point, the angle between the line connecting this point with the geographical center of the earth and the equatorial plane.
2. •
   At a given point, the angle between magnetic north and true north.
3. •
   A refusal.
4. •
   Declension.
5. •
   The gradual decline in the overall fundamental frequency or pitch of speech over the course of an utterance, independent of local variations such as tones and pitch accents.
6. •
   (no longer used) The act or state of falling off or declining from excellence or perfection; deterioration; decay; decline.

   • Summer […] is not looked on as a time of declination or decay. — 1635
7. •
   (no longer used) The act or state of bending downward; inclination.
8. •
   (no longer used) Deviation.