preadaptationPronunciation: /ˌpriːadəpˈteɪʃ(ə)n/Definition of preadaptation noun Biology an adaptation which serves a different purpose from the one for which it evolved. [mass noun] the process by which a preadaptation arises. Derivatives preadapt verb preadaptation in other Oxford dictionaries Definition of preadaptation in the US English dictionary