DefinitionThe conversion or conversion of units of different units of measurement into the same quantity, usually by a conversion equation or unit conversion. Physical properties such as length, weight, time, temperature have their own units. These units are standards used to express quantities. measurement. In science, engineering, and nearly all types of quantitative measurements, the use of conversions and units is universally accepted and provides a percentage of success for all measurements in equation ratio. Example - Converting from meters to miles: Divide by 1000 because there are 1000 meters in a mile.