decay vs expansion

decay

noun
  • The process or result of being gradually decomposed. 

  • A deterioration of condition; loss of status or fortune. 

  • The situation, in programming languages such as C, where an array loses its type and dimensions and is reduced to a pointer, for example by passing it to a function. 

verb
  • To undergo bit rot, that is, gradual degradation. 

  • To deteriorate, to get worse, to lose strength or health, to decline in quality. 

  • To undergo optical decay, that is, to relax to a less excited state, usually by emitting a photon or phonon. 

  • Loss of airspeed due to drag. 

  • To undergo software rot, that is, to fail to be updated in a changing environment, so as to eventually become legacy or obsolete. 

  • To change by undergoing fission, by emitting radiation, or by capturing or losing one or more electrons; to undergo radioactive decay. 

  • To cause to rot or deteriorate. 

  • Of an array: to lose its type and dimensions and be reduced to a pointer, for example when passed to a function. 

  • To rot, to go bad. 

  • To undergo prolonged reduction in altitude (above the orbited body). 

expansion

noun
  • A new addition. 

  • A product to be used with a previous product. 

  • That which is expanded; expanse; extended surface. 

  • The operation of steam in a cylinder after its communication with the boiler has been cut off, by which it continues to exert pressure upon the moving piston. 

  • The replacement of a short name (e.g., acronym, initialism, alphanumeric symbol, abbreviation) with the longer name that is synonymous with it, as when spelling out acronyms to ensure clarity for a general audience. 

  • The string of text thus substituted. 

  • An act, process, or instance of expanding. 

  • The fractional change in unit length per unit length per unit temperature change. 

How often have the words decay and expansion occurred in a corpus of books? (source: Google Ngram Viewer )