Category: Standards and measurement stubs Conversion of units refers to conversion factors between different units of measurement for the same quantity. ... An acre foot is a unit of volume commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, and river flows. ... An acre is the name of a unit of area in a number of different systems, including Imperial units and United States customary units. ... A Scottish acre (Scottish Gaelic: acair) was a land measurement used in the country. ...