De-clēn'sion, n.

n. [Fr. déclinaison and déclination, Pr. declinazo, declinatio, Sp. declinacion, It. declinazione, Lat. declinatio, from declinare. See DECLINE.]

1. That which is inclining, or appears to incline; declination; descent; slope. “The declension of the land from that place to the sea.” Burnet.
2. A falling off from excellence or perfection; a downward tendency; deterioration; decay; as, the declension of virtue, of science, of a state, &c.

Seduced the base and pitch of all his thoughts To base declension. Shak.

3. The act of courteously refusing; act of declining; a declinature; as, the declension of a nomination, &c.
4. (Gram.) (a.) Inflection of a word, according to its grammatical cases. (b.) The form of the inflection of a word declined by cases; as, the first or second declension. (c.) Rehearsing a word as declined.

Declension of the needle, declination of the needle.