noun

• (obsolete) A cassowary (genus Casuarius).
• A large flightless bird native to Australia, Dromaius novaehollandiae.
• A dark constellation in Southern Celestial Hemisphere, Dome of the Sky; A constellation or asterism from Australian aborigine cultures, a dark constellation pattern formed by an arrangement of dark nebulae in the sky, blotting out background stars, appearing akin to the emu giant bird of Australia.
• (physics) Initialism of electromagnetic unit. [Any of the various units to measure electricity and magnetism in the CGS (now replaced by SI) system of units; abbreviated emu, e.m.u., or EMU.]
• (computing, video games, informal) Clipping of emulator. [A person or thing that emulates.]
• (European Union) Initialism of European Monetary Union.
• Initialism of Eastern Mennonite University.
• (computing) Initialism of English metric unit (“1/360,000-th of a centimetre, or, 1/914400-th of an inch”).
• (rail transport, countable) Initialism of electric multiple unit. [(rail transport) A multiple unit train powered by electricity, abbreviated EMU.]
• (cgs) Alternative form of emu or e.m.u.; Initialism of electromagnetic unit.
• (automotive engineering) Initialism of engine management unit.
• (astronautics) Initialism of extravehicular mobility unit (“spacesuit”).
• (economics) Initialism of economic and monetary union.