Definition: A fluid ounce per hour (fl-oz/h) is a unit of volumetric flow rate that measures the volume of a fluid passing through a surface per unit of time. It represents the amount of fluid volume, measured in fluid ounces, that flows every hour.

History/origin: The fluid ounce is a unit of volume in the imperial and United States customary systems of measurement. Its historical origins can be traced back to systems of apothecary measures and later standardization for commercial purposes. The 'per hour' component indicates a rate of change over time.

Current use: Fluid ounces per hour is used in applications where measuring very slow fluid flow rates is needed, such as small drip systems, certain chemical processes, or laboratory experiments requiring slow infusion rates.