From Longman Dictionary of Contemporary Englishmouse potatoˈmouse poˌtato noun [countable] informal someone who spends a lot of time at home sitting and using a computer → couch potatoFrom Longman Business Dictionarymouse potatoˈmouse poˌtato noun (plural mouse potatoes) [countable] informal someone who spends a lot of time playing on a computer, especially using the InternetMy 14-year old son has become a mouse potato ever since he was given his own PC for his birthday.