The function of a trait can, and often does, change over time. Several terms have been used to describe this: "preadaptation", "exaptation", "cooption". 'Preadaptation' is the most common term used when a preexisting structure or trait inherited from an ancestor evolves a different function. It was the term used by Julian Huxley and Ernst Mayr. The term 'pre-' does not mean any foresight, it just means the adaptation was already available, serving some older function. 'Exaptation' was Stephen J. Gould's word.