LIBRA (lb) & POUND: A Unit of Mass LIBRA (lb): The libra is used in scales or balance in Latin language.The libra is an ancient Roman unit of mass that was equivalent to approximately 328.9 grams. It was divided into 12 unciae. The singular of ‘unciae’ is ‘uncia’. Other name of ‘uncia’ is ‘ounces’. The libra is the origin … Continue reading LIBRA (lb) & POUND: A Unit of Mass