Hard measles: An acute highly contagious viral disease with fever, runny nose, cough, red eyes, and a spreading skin rash. The eight-day measles is the ordinary measles, also known as rubeola, a potentially disastrous disease. Measles may be complicated by ear infections, pneumonia, encephalitis (that can cause convulsions, mental retardation. and even death), the sudden onset of low blood platelet levels with severe bleeding (acute thrombocytopenic purpura) or a chronic brain disease that occurs months to often years after an attack of measles (subacute sclerosing panencephalitis). During pregnancy measles may trigger miscarriages or premature delivery. Measles can be prevented through vaccination. The disease is also called (depending on how long you think it lasts) the seven-day measles, eight-day measles, nine-day measles, or the ten-day measles, and morbilli. The name measles comes from the Middle English maselen meaning many little spots referring, of course, to the rash.