SOU (0. Fr. sol, Lat, solidus, sc. nummus), the name of the bronze 5-centime French coin, corresponding to the English " halfpenny." It is still colloquially used in France in reckoning, and the franc, 2 and 5-franc pieces are known as piece de vingt, quarante and cent sous respectively. The solidus was originally a gold coin, first struck c. A.D. 312 by Constantine to take the place of the aureus. In the Eastern Empire this gold coin was the standard down to 1453, and, as the " bezant," circulated from Portugal to the Indies. In the West after Pippin gold coinage ceased and the solidus in silver became the standard, one pound of silver making 22 sols (solidi) and 264 denier 'S (denarii). Under Charlemagne one pound of silver =20 sols =240 deniers. The lime (libra), the sol and the denier formed the universal money of account throughout France until the Revolution; and they have left their mark on the English money symbols s. d., for pounds, shillings and pence.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)