Answer: ATMOS

AnswerCrossword Clue
ATMOSBrand of clock powered by changes in temperature
ATMOSSelf-winding clock
ATMOSGreek for "vapor"
ATMOSAir pressure at sea level: for short.
ATMOSAir pressure measurement.
ATMOSGreek word for steam.
ATMOSSelf-winding mercury clock
ATMOSPrefixes meaning vapors
ATMOSVapor, in Greece
ATMOS... clock (self-winding timepiece)
ATMOS... Energy (big natural gas utility)