1. [n]  the organic phenomenon of rotting
2. [n]  a gradual decrease; as of stored charge or current
3. [n]  the process of gradually becoming inferior
4. [n]  the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation
5. [n]  an inferior state resulting from the process of decaying; "the corpse was in an advanced state of decay"; "the house had fallen into a serious state of decay and disrepair"
6. [v]  undergo decay or decomposition
7. [v]  fall into decay or ruin; "The unoccupied house started to decay"
8. [v]  lose a stored charge, magnetic flux, or current; as of particles in nuclear fission

1. \De*cay"\, v. i. [imp. & p. p. {Decayed}; p. pr. & vb. n.
   {Decaying}.] [OF. decaeir, dechaer, decheoir, F. d['e]choir,
   to decline, fall, become less; L. de- + cadere to fall. See
   {Chance}.]
   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; as, a tree decays; fortunes
   decay; hopes decay.
   
         Ill fares the land, to hastening ills a prey, Where
         wealth accumulates and men decay.        --Goldsmith.
   
   

2. \De*cay"\, v. t.
   1. To cause to decay; to impair. [R.]
   
            Infirmity, that decays the wise.      --Shak.
   
   2. To destroy. [Obs.] --Shak.
   
   

3. \De*cay"\, n.
   1. Gradual failure of health, strength, soundness,
      prosperity, or of any species of excellence or perfection;
      tendency toward dissolution or extinction; corruption;
      rottenness; decline; deterioration; as, the decay of the
      body; the decay of virtue; the decay of the Roman empire;
      a castle in decay.
   
            Perhaps my God, though he be far before, May turn,
            and take me by the hand, and more - May strengthen
            my decays.                            --Herbert.
   
            His [Johnson's] failure was not to be ascribed to
            intellectual decay.                   --Macaulay.
   
            Which has caused the decay of the consonants to
            follow somewhat different laws.       --James Byrne.
   
   2. Destruction; death. [Obs.] --Spenser.
   
   3. Cause of decay. [R.]
   
            He that plots to be the only figure among ciphers,
            is the decay of the whole age.        --Bacon.
   
   Syn: Decline; consumption. See {Decline}.
   
   

[Nuclear physics] An automatic conversion which is applied to most array-valued expressions in c; they "decay into" pointer-valued expressions pointing to the array's first element. This term is not used in the official standard for the language.

[jargon file]