Convert from oncia [Italy] to arroba [Portugal]

Unit Definition (oncia [Italy])
The onça, once, oncia, onza is traditional names for the ounce unit in Romance languages. The Italian oncia or onza is no longer used, but traditionally it equaled 1/12 libra or about 27.3 grams (0.96 ounce).

Unit Definition (arroba [Portugal])
The arroba [Portugal] is a traditional unit of weight in Spain and Portugal, equal to 1/4 quintal. However, the Spanish and Portuguese quintals are of different sizes. In Portugal and Brazil, the arroba traditionally equals 32.38 pounds (14.69 kilograms, but in recent years this has been "metrized" to be exactly 15 kilograms). The arroba has also been used as a metric unit equal to exactly 15 kilograms. The name of the unit comes from ar rub', Arabic for "the quarter."