stereochemistry (stÄr'Ä-Å-kÄm'Ä­-strÄ) The branch of chemistry that deals with the spatial arrangements of atoms in molecules and with the chemical and physical effects of these arrangements.
ECU. Short for Electronic Control Unit, the ECU is a name given to a device that controls one or more electrical systems in a vehicle. It operates much like the BIOS does in a computer.
The Extravehicular Mobility Unit (EMU) is an independent anthropomorphic spacesuit that provides environmental protection, mobility, life support, and communications for astronauts performing extra-vehicular activity (EVA) in Earth orbit.