Plain English Meaning
A measure of how much power something produces or uses, equal to one thousand watts. It tells you how quickly an engine is doing work.
Full Definition
A unit of power equal to 1,000 watts, used to express the rate at which energy is produced or used. In aviation performance discussions, kilowatts (kW) are sometimes used in place of horsepower to describe an engine's power output, where 1 horsepower equals approximately 0.746 kilowatts.
Context Anchor
Seen in climb-performance discussions, aircraft performance data, and comparisons between horsepower and metric or electric power ratings.
Derivation
From the Greek 'kilo' meaning thousand, and 'watt' named after James Watt, the Scottish engineer who improved the steam engine. So a kilowatt is literally a thousand watts — a thousand units of the power measurement named after Watt.