While we're on the subject -
EGT made sense as an abbreviation for
Exhaust gas temperature when is was measured at the engine's exhaust. This was once called tailpipe temperature or TPT.
However, today many (most?) engines have their temperature taken several turbine stages upstream of the exhaust, typically between the HPT and LPT, and thus several hundred degrees hotter than the tailpipe. Some aircraft call it ITT (Inter-turbine temperature) which makes great sense, but EGT is still the more common (if obsolete) label.
