Why is the ninth month called September?
Old English mil, from West Germanic *milja (cf. Middle Dutch mile, Dutch mijl, Old High German mila, German meile), from Latin mila "thousands," plural of mille "a thousand" (neuter plural was mistaken in Germanic as a fem. singular), of unknown origin.
The Latin word also is the source of French mille, Italian miglio, Spanish milla. The Scandinavian words (Old Norse mila, etc.) are from English. An ancient Roman mile was 1,000 double paces (one step with each foot), for about 4,860 feet, but there were many local variants and a modern statute mile is about 400 feet longer. In Germany, Holland, and Scandinavia in the Middle Ages, the Latin word was applied arbitrarily to the ancient Germanic rasta, a measure of from 3.25 to 6 English miles. Mile-a-minute (adj.) "very fast" is attested from 1957.
(from Lat. mille, "a thousand;" Matt. 5:41), a Roman measure of 1,000 paces of 5 feet each. Thus the Roman mile has 1618 yards, being 142 yards shorter than the English mile.