Definition of "retrofit" []

• To provide (a jet, automobile, computer, or factory, for example) with parts, devices, or equipment not in existence or available at the time of original manufacture. (verb-transitive)
• To install or fit (a device or system, for example) for use in or on an existing structure, especially an older dwelling. (verb-transitive)
• To fit into or onto equipment already in existence or service. (verb-intransitive)
• To substitute new or modernized parts or systems for older equipment: an industrial plant that was retrofitting to meet new safety regulations. (verb-intransitive)
• Something that has been retrofitted or that has undergone retrofitting. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "I put in retrofit electrical boxes, network jacks and wall plates."
• "Work has already begun on the $20 million retrofit, which is being done as a joint project involving the Clinton Climate Initiative, Rocky Mountain Institute, Johnson Controls, and Jones Lang LaSalle, and is part of a greater $500 million in planned renovations."
• "But there are lighting markets that LEDs will have difficulty penetrating even when they are the most efficient white light source, namely retrofit markets for standard light bulbs (i.e. you will keep your CFLs for some time yet.)"