accretion vs increment

accretion

noun
  • The act of increasing, or the matter added, by an accession of parts externally; an extraneous addition. 

  • Gain to an heir or legatee; failure of a coheir to the same succession, or a co-legatee of the same thing, to take his share percentage. 

  • The formation of planets and other bodies by collection of material through gravity. 

  • The gradual increase of land by deposition of water-borne sediment. 

  • Something added externally to promote the external growth of an item. 

  • A growing together of parts naturally separate, as of the fingers or toes. 

  • Concretion; coherence of separate particles. 

  • The act of increasing by natural growth; especially the increase of organic bodies by the internal accession of parts; organic growth. 

  • The adhering of property to something else, by which the owner of one thing becomes possessed of a right to another; generally, gain of land by the washing up of sand or sail from the sea or a river, or by a gradual recession of the water from the usual watermark. 

increment

noun
  • The action of increasing or becoming greater. 

  • The amount of time added to a player's clock after each move. 

  • The amount of increase. 

  • The waxing of the moon. 

  • An amplification without strict climax, as in the following passage: "Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report, […] think on these things." 

  • A syllable in excess of the number of the nominative singular or the second-person singular present indicative. 

verb
  • To increase by steps or by a step, especially by one. 

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