Definition of "preformed" [preformed]

• Simple past tense and past participle of preform. (verb)
• Formed, constructed or assembled in advance (adjective)

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• "You can buy lots of that in preformed plastic for very cheap or use scrap pieces."
• "The body gets vitamin A in two forms: from retinol, or "preformed" vitamin A, and from beta-carotene, which the body converts into vitamin A."
• "The study also showed that all volunteers consumed only about a third of their recommended intake from 'preformed' vitamin A - the form found in dairy products such as eggs and milk - indicating that those volunteers carrying the genetic variation were not eating enough vitamin A-rich foods to reach the optimum level their body required to function."