the power output of a piston engine calculated from the mean effective pressure in the cylinder as derived from an indicator diagram and the speed of the engine in revolutions per minute
indicated horsepower in American English
noun
the horsepower of a reciprocating engine as shown by an indicator record
Abbreviation: ihp, IHP
Word origin
[1870–75]This word is first recorded in the period 1870–75. Other words that entered Englishat around the same time include: Mafia, Victorian, asymmetric, billing, fifth wheel