United States customary units are a system of measurements commonly used in the United States. The US customary system developed from English units which were in use in the British Empire before American independence. Consequently most US units are virtually identical to the British imperial units. However, the British system was overhauled in 1824, changing the definitions of some units used there, so several differences exist between the two systems. The majority of US customary units were redefined in terms of the meter and the kilogram with the Mendenhall Order of 1893, and in practice...

Metric time is the measure of time interval using the metric system, which defines the second as the base unit of time, and multiple and submultiple units formed with metric prefixes, such as kiloseconds and milliseconds. It does not define the time of day, as this is defined by various time scales, which may be based upon the metric definition of the second. Other units of time, the minute, hour, and day, are accepted for use with the modern metric system, but are not part of it. History Although part of the decimal metric system, the second derives its name from the sexagesimal system...

The French Republican Calendar () or French Revolutionary Calendar (calendrier révolutionnaire français) was a calendar created and implemented during the French Revolution, and used by the French government for about 12 years from late 1793 to 1805, and for 18 days by the Paris Commune in 1871. The revolutionary system was designed in part to remove all religious and royalist influences from the calendar, and was part of a larger attempt at decimalisation in France. Overview and origins History The days of the French Revolution and Republic saw many efforts to sweep away various trapp...