Decline

The term declination can refer to:

• Grammatical decline, orderly series of different forms that adopt a word based on the cases in which it is used.
• Astronomical decline, one of the coordinates of the celestial sphere, equivalent to latitude on Earth.
• Solar decline, is a particular application of astronomical decline for the movement of the sun.
• Magnetic decline, angle between the local magnetic north and the real north (or geographical north).
• Declination wall, orientation angle of the vertical solar clock used in its design.