extension vs retrofit

extension

noun
  • An optional software component that adds functionality to an application. 

  • The set of tuples of values that, used as arguments, satisfy the predicate. 

  • Capacity of a concept or general term to include a greater or smaller number of objects; — correlative of intension. 

  • A file extension. 

  • University programs that are targeted at the broader (usually adults) community whose participants are not full-time enrolled students. 

  • That property of a body by which it occupies a portion of space (or time, e.g. "spatiotemporal extension") 

  • A part of a building that has been extended from the original 

  • semantic widening, broadening of meaning 

  • A simple offensive action, consisting of extending the weapon arm forward. 

  • The act of extending; a stretching out; enlargement in length, breadth, or time; an increase 

  • The operation of stretching a broken bone so as to bring the fragments into the same straight line. 

  • The state of being extended 

  • A written engagement on the part of a creditor, allowing a debtor further time to pay a debt. 

  • A numerical code used to specify a specific telephone in a telecommunication network. 

  • An exercise in which an arm or leg is straightened against resistance. 

  • A kind of derivative morpheme applied to verbs in Bantu languages. 

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 extension and retrofit occurred in a corpus of books? (source: Google Ngram Viewer )