Definition of "retrofit"

(transitive)

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

   Quotations

   • Trams dating from 2012 have been retro-fitted with lithium batteries, with the conversions starting in 2018.

     2020 January 2, Richard Clinnick, “Midlands Metro Welcomes New Catenary-free Trams”, in Rail, Peterborough, Cambridgeshire: Bauer Media, page 16

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

3. (computing) 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.”)  examples

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

(intransitive) To supply a device, structure, etc., with new components or parts that were not previously available or installed.  examples

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

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