LIBRA, in Astronomy, one of the 12 signs of the zodiac, and exactly opposite to Aries; so called because when the sun is in this sign at the autumnal equinox, the days and nights are equal as if weighed in a balance.—The stars in this constellation according to Ptolemy are 17, Tycho 10, Hevelius 20, and Flamsteed 51.
LIBRA also denotes the ancient Roman pound, borrowed from the Sicilians, who called it litra.
The libra was divided into 12 uncie or ounces, and the ounce into 24 scruples.
The divisions of the libra were, the uncia, one twelfth; the sextans, one sixth; the quadrans, one fourth; the triens, one third; the quincunx, five ounces; the semis, six; the septunx, seven; the bes, eight; the dodrans, nine; the dextrans, ten; the deunx, eleven; lastly, the as weighed twelve ounces or one libra.
The Roman libra was used in France for the proportions of their coin till the time of Charlemagne, or perhaps till that of Philip I. in 1093, their sols being so proportioned, as that 20 of them were equal to the libra. By degrees it became a term of account: and every thing of the value of twenty sols was called a livre.