|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
The acre-inch is a unit of volume commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water, and river flows.
A hogshead (abbreviated "Hhd", plural "Hhds") is a large cask of liquid (or, less often, of a food commodity). More specifically, it refers to a specified volume, measured in either imperial or US customary measures, primarily applied to alcoholic beverages, such as wine, ale, or cider.