retrofit

American  

[re-troh-fit, re-troh-fit, re-troh-fit] / ˈrɛ troʊˌfɪt, ˌrɛ troʊˈfɪt, ˈrɛ troʊˌfɪt /

verb (used with object)

retrofitted, retrofit, retrofitting

1. to modify equipment (in airplanes, automobiles, a factory, etc.) that is already in service using parts developed or made available after the time of original manufacture.

2. to install, fit, or adapt (a device or system) for use with something older.

   to retrofit solar heating to a poorly insulated house.

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verb (used without object)

retrofitted, retrofit, retrofitting

1. (of new or modified parts, equipment, etc.) to fit into or onto existing equipment.

2. to replace existing parts, equipment, etc., with updated parts or systems.

noun

1. something that has been retrofitted.

2. an instance of updating, enlarging, etc., with new or modified equipment.

   A retrofit could save thousands of dollars.

adjective

1. being or characterized by a retrofit.

   retrofit units.

retrofit British  

/ ˈrɛtrəʊˌfɪt /

verb

1. (tr) to equip (a vehicle, piece of equipment, etc) with new parts, safety devices, etc, after manufacture

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Other Word Forms

• retrofittable adjective

Etymology

Origin of retrofit

retro- + fit ¹

Example Sentences

The company will use the funding to conduct a paid pilot with a Class 1 railroad, testing its battery retrofit and dynamic charging system.

From The Wall Street Journal • Mar. 31, 2026

The Driver and Vehicle Standards Agency has said it has stepped up a crackdown on retrofit bulbs, with sellers facing potential fines of up to £1,000.

From BBC • Feb. 18, 2026

Riot Platforms will make around $90 million in capital expenditures to retrofit the Rockdale facility.

From Barron's • Jan. 16, 2026

A report from the community development research nonprofit Headwaters Economics found a complete home retrofit using affordable materials costs between $23,000 and $40,000.

From Los Angeles Times • Nov. 24, 2025

The Center has since benefitted by a forty-million-dollar retrofit, but there's still enough forest and swamp on the facility for the Border Patrol to put in tracking practice.

From The Hacker Crackdown, law and disorder on the electronic frontier by Sterling, Bruce