Declination (dec) is an astronomical term associated with the equatorial coordinate system. Dec is comparable to latitude, projected unto the celestial sphere, and is measured in degrees north of the celestial equator. Therefore, points north of the celestial equator have positive declination, while those to the south have negative declination.
Declination is used in some contexts that rule out astronomical declination, to mean the same as magnetic declination.
Declination is occasionally and erroneously used to refer to the linguistic term declension.