High Quality Content by WIKIPEDIA articles! In modern usage, metric is used almost exclusively in commercial transactions. These units are mostly historical, although they are still used in some limited contexts and in Maltese idioms and set phrases. Many of these terms are directly related to Arabic units. The Weights and Measures Ordinance of 1921 established uniformity in the conversion of such weights and measures. All these measures were defined as simple multiples of the Imperial units then in use in Britain.