Stadium
Etymology

"Stadium" is the Latin form of the Greek word " stadion " (στάδιον), a measure of length equalling the length of 600 human feet. As feet are of variable length the exact length of a stadion depends on the exact length adopted for 1 foot at a given place and time. Although in modern terms 1 stadion = 600 ft (180 m), in a given historical context it may actually signify a length up to 15% larger or smaller.

The equivalent Roman measure, the stadium, had a similar length – about 185 m (607 ft) – but instead of being defined in feet was defined using the Roman standard passus to be a distance of 125 passūs (double-paces).

The English use of stadium comes from the tiered infrastructure surrounding a Roman track of such length.

Most dictionaries provide for both stadiums and stadia as valid English plurals.
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