meaning of decay
/dÉªËkeÉª/. noun. Learner's definition of DECAY. [noncount]. : the process or result of decaying: such as. a: the process or result of being slowly destroyed by natural processes. the decay of dead plants and leaves. tooth decay. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples. b: the slow loss of strength, health, etc.