Scottish acre Wikipedia
A Scottish or Scots acre (Scottish Gaelic: acair) was a land measurement used in Scotland. It was standardised in 1661. When the Weights and Measures Act of 1824 was implemented the English System was standardised into the Imperial System and Imperial acres were imposed throughout the United Kingdom, including in Scotland and indeed throughout the British Empire from that point on. However, since then the metric system has come to be used in Scotland, as in the rest of the United Kingdom..
Equivalent to -Scottish measures
5,080 square metres , 0.508 hectares
1.3 acres (English)