Emily Dickinson Lexicon

DE-CLIV'I-TY, n. [L. declivitas, from declivis, sloping; de and clivus. See Cliff.]

Declination from a horizontal line; descent of land; inclination downward; a slope; a gradual descent of the earth, of a rock or other thing; chiefly used of the earth, and opposed to acclivity, or ascent; the same slope, considered as descending, being a declivity, and considered as ascending, an acclivity.