In 1965, Owen Maclaren, an aeronautical engineer, listened to his daughter complain about traveling from England to America with her heavy pram. Maclaren knew that she needed something with a light frame that could fold up compactly. Using his knowledge of aeroplanes, Maclaren designed a stroller with an aluminum frame and created the first true umbrella stroller. He then went on to found Maclaren which manufactured and sold his new design. _Wikipedia
These lightweight strollers that folded up so like an umbrella does, were nicknamed umbrella strollers.