DECLIVITY

descent, declivity, fall, decline, declination, declension, downslope

(noun) a downward slope or bend

Source: WordNet® 3.1

Etymology

Noun

declivity (plural declivities)

(geomorphology) The downward slope of a hill; the downward slope of a curve.

A downward bend in a path.

(entomology) An inward curve of the exoskeleton of an insect, such as between body segments; a segment of an insect's body where the exoskeleton curves inward.

Source: Wiktionary

De*cliv"i*ty, n.; pl. Declivities. Etym: [L. declivitas, fr. declivis sloping, downhill; de + clivus a slope, a hill; akin to clinare to incline: cf. F. déclivité. See Decline.]

1. Deviation from a horizontal line; gradual descent of surface; inclination downward; slope; -- opposed to acclivity, or ascent; the same slope, considered as descending, being a declivity, which, considered as ascending, is an acclivity.

2. A descending surface; a sloping place. Commodious declivities and channels for the passage of the waters. Derham.

Source: Webster’s Unabridged Dictionary 1913 Edition