megameter UK /mɛˈɡɐˌmɪtə/US /mɛˈɡɐˌmɪtəɹ/ noun3 •A distance of 1,000 km.Common numbers like distances would never be expressed in megameters or nanomiles — it would bring us too close to the Dilbertian world of pocket protectors and calculator holsters. — 2009 •An instrument for determining longitude by observation of the stars. •A micrometer. formsmegameters