Meaning

noun change toward something smaller or lower

noun a condition inferior to an earlier condition; a gradual falling off from a better state

noun a gradual decrease; as of stored charge or current

originFrom Middle English declinen, and ultimately Latin declīnō (“to bend, turn aside, deflect, inflect, decline”, from dē- (“down”) + clīnō (“to bend, to incline”)), from Proto-Indo-European *ḱley- (English lean). The senses arrived from two separate pathways in Middle English: * The grammatical sense came from Old English declīnian, which was borrowed directly from the Latin etymon. * All senses…

Etymology from Wiktionary, CC BY-SA 3.0