additive vs retrofit

additive

noun
  • A substance added to another substance or product to produce specific properties in the combined substance. 

  • A word or phrase that adds something, such as also, even, or nor. 

adj
  • Of or pertaining to genes (or the interaction etc. of such genes) which govern the same trait and whose effects work together on the phenotype. 

  • Pertaining to chemical addition. 

  • Pertaining to addition; that can be, or has been, added. 

  • That is distributive over addition. 

  • Whose operator is identified as addition. 

retrofit

noun
  • A change made to a device, structure, etc., by introducing components or parts that were not previously available or installed. 

  • An act of supplying a device, structure, etc., with new components or parts that were not previously available or installed; a retrofitting. 

verb
  • To supply (a device, structure, etc.) with new components or parts that were not previously available or installed; to modernize. 

  • Synonym of backport (“to retroactively supply a fix or feature to a previous version of a software product at the same time or after supplying it to the current version.”) 

  • To give new characteristics or make alterations (to someone or something) to suit them to changed circumstances. 

  • To supply a device, structure, etc., with new components or parts that were not previously available or installed. 

  • To add or substitute (new components or parts) that were not previously available for or installed in a device, structure, etc. 

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