In astronomy, declination (abbreviated dec; symbol δ) is one of the two direction coordinates of a point on the celestial sphere in the equatorial coordinate system, the other being either right ascension or hour angle. Declination's angular distance is measured north or south of the celestial equator, along the hour circle passing through the point in question.
The root of word the declination (Latin, declinatio) means "a bending away" or "a bending down". It comes from the same root as the words incline ("bend toward") and recline ("bend backward").
Source: wikipedia, NASA