Definition: A kilolitre per second (kl/s) is a unit of volumetric flow rate equal to 1,000 liters passing a point in one second. It is used to measure large volumes of liquid flow.

History/origin: The kilolitre is a metric unit of volume, derived from the litre (symbol: L), with the prefix 'kilo-' indicating a factor of 1000. The 'per second' component indicates a rate of flow over time, making the unit suitable for flow rate measurements. Its origin is directly tied to the establishment of the metric system in France in the late 18th century.

Current use: Kl/s is used in industrial processes, water management, and large-scale fluid transfer applications where quantifying high flow rates is necessary. Examples include measuring water flow in large pipelines, industrial coolant systems, and discharge rates from reservoirs.