A tron was a weighing machine in medieval Scotland, usually located in the marketplaces of burghs. There are various areas of several Scottish towns that are named for them. Etymologically the word is derived from the Old French tronel or troneau, meaning "balance".[1]
From the 12th century the city fathers of Scottish burghs needed to standardise weights and measurements, partly to collect the correct taxation on goods, and partly to stop unscrupulous merchants shortchanging citizens. Trons were set up in marketplaces throughout Scotland, with each burgh with its own set of, sometimes differing, weights.[1] Some burghs had more than one tron; in Edinburgh a butter tron was located at the head of the West Bow, while a salt tron was located further down the Royal Mile.[2][3]