Definition: A gallon per second (gal/s) is a unit of flow rate that measures the volume of fluid passing a point per unit time, specifically in gallons and seconds. It is commonly used in contexts where relatively large volumes of liquids are transferred quickly.

History/origin: The gallon is a unit of volume with historical roots in various systems of liquid measurement. The 'per second' component simply standardizes the volume measurement to a time interval. Its origin ties back to practical needs in trade and industry to quantify liquid flow.

Current use: It is used in various applications, including industrial processes, water treatment plants, and contexts where high flow rates are significant, such as in firefighting or large-scale pumping operations. It provides a clear measure of liquid flow speed.