from The American Heritage® Dictionary of the English Language, 4th Edition
- intransitive v. Biology To break down into component parts; rot.
- intransitive v. Physics To disintegrate or diminish by radioactive decay.
- intransitive v. Electronics To decrease gradually in magnitude. Used of voltage or current.
- intransitive v. Aerospace To decrease in orbit. Used of an artificial satellite.
- intransitive v. To fall into ruin: a civilization that had begun to decay.
- intransitive v. Pathology To decline in health or vigor; waste away.
- intransitive v. To decline from a state of normality, excellence, or prosperity; deteriorate.
- transitive v. To cause to decay.
- n. The destruction or decomposition of organic matter as a result of bacterial or fungal action; rot.
- n. Rotted matter.
- n. Physics Radioactive decay.
- n. Aerospace The decrease in orbital altitude of an artificial satellite as a result of conditions such as atmospheric drag.
- n. A gradual deterioration to an inferior state: tooth decay; urban decay.
- n. A falling into ruin.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The process or result of being gradually decomposed.
- n. A deterioration of condition.
- v. To deteriorate, to get worse, to lose strength or health, to decline in quality.
- v. To rot, to go bad.
- v. To change by undergoing fission, by emitting radiation, or by capturing or losing one or more electrons.
- v. To undergo optical decay, that is, to relax to a less excited state, usually by emitting a photon or phonon.
- v. To cause to rot or deteriorate.
from the GNU version of the Collaborative International Dictionary of English
- intransitive v. To pass gradually from a sound, prosperous, or perfect state, to one of imperfection, adversity, or dissolution; to waste away; to decline; to fail; to become weak, corrupt, or disintegrated; to rot; to perish
- transitive v. To cause to decay; to impair.
- transitive v. To destroy.
- n. Gradual failure of health, strength, soundness, prosperity, or of any species of excellence or perfection; tendency toward dissolution or extinction; corruption; rottenness; decline; deterioration
- n. Destruction; death.
- n. Cause of decay.
from The Century Dictionary and Cyclopedia
- To pass gradually from a sound or perfect state to a less perfect state, or toward weakness or dissolution; fall into an inferior condition or state; specifically, become decomposed or corrupted; rot.
- Synonyms Putrefy, Corrupt, etc. See rot.
- To cause to become unsound or impaired; cause to deteriorate; impair; bring to a worse state.
- n. Gradual loss of soundness or perfection; a falling by degrees into an impaired condition or state; impairment in general; loss of strength, health, intellect, etc.
- n. Specifically Decomposition; putrefaction; rot.
- n. 3. Death; dissolution.
- n. . A disease; especially, consumption.
- n. . A cause of decay.
- n. Loss of fortune or property; misfortune; ruin : applied to persons.
- n. . plural Ruins.
- n. Synonyms Decline, decadence, deterioration, degeneracy, withering.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the process of gradually becoming inferior
- n. a gradual decrease; as of stored charge or current
- n. the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation
- v. undergo decay or decomposition
- v. lose a stored charge, magnetic flux, or current
- v. fall into decay or ruin
- n. the organic phenomenon of rotting
- n. an inferior state resulting from the process of decaying
Middle English decayen, from Old French decair, from Vulgar Latin *dēcadere : Latin dē-, de- + Latin cadere, to fall; see kad- in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Old French decair ("to fall away, decay, decline"), from Medieval Latin *decadere, restored form of Latin decidere ("to fall away, fail, sink, perish"), from de ("down") + cadere ("to fall"); compare decadent and decadence. (Wiktionary)