A maroon is a type of rocket which makes a loud banging report (noise) and a bright flash. It is used as an alarm or warning, for example the BritishRoyal National Lifeboat Institution uses these rockets to call the crew when the lifeboat needs to be launched. Another example was as a signal on a railway, to alert oncoming trains that they must stop due to unexpected accident or track work ahead. Used by British spotters in WWI located around the cities. They would fire when German bombers were approaching.