plethron

{{Short description|Ancient unit of Greek measurement (unit of length)}}

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Plethron ({{langx|grc|{{linktext|πλέθρον}}}}, plural plethra) is an ancient unit of Greek measurement equal to 97 to 100 Greek feet (ποῦς, pous; c. 30 centimeters),{{Cite web| author = Calvert, J.B.

| date = 13 May 2010 | title = Old Units of Length | department=MySite.DU.edu | publisher = University of Denver | url=https://mysite.du.edu/~jcalvert/tech/oldleng.htm |access-date = 3 March 2020}} Original creation date, 3 July 1999.{{better source|date=March 2020}} although the measures for plethra may have varied from polis to polis.{{citation needed | date = March 2020}} This was roughly the width of a typical ancient Greek athletic running-track.{{citation needed | date = March 2020}}

A plethron could also be used as a unit of measured area, and reference to the unit in defining the size of a wrestling area is made by Libanius.Libanius, Orationes, Chapter 10.{{full|date=March 2020}}{{full|date=March 2020}}{{primary source inline|date=March 2020}} A square plethron of c. 30 by 30 meters was used as the standard dimensions of a Greek wrestling square, since such competitions were held within the racing track in ancient Greece.{{citation needed | date = March 2020}} In other connotations, it functioned as the Greek acre, and varied in size to accommodate the amount of land a team of oxen could plow in a day.{{citation needed | date = March 2020}}

The plethron continued to be used in the Byzantine Empire, where its variant uses were ultimately codified to refer to an area defined by sides of 100 feet or 40 paces (βῆμα, bema).{{cite journal | author = Ménage, V. L. | date = 1973 | title = Review of Speros Vryonis, Jr. 'The decline of medieval Hellenism in Asia Minor and the process of islamization from the eleventh through the fifteenth century' [Berkeley, 1971] | journal = Bulletin of the School of Oriental and African Studies | publisher = University of London | volume = 36 | issue = 3 | pages = 659–661 | doi = 10.1017/S0041977X00120117 | jstor = 613605 }} See also Schilbach, Erich (date not provided) Byzantinische Metrologie.{{full|date=March 2020}} Ultimately, the unit came to be known as the "stremma", which continues as a metric unit in modern Greece.