Final answer:
The term 'Highland' is used exclusively for scotch distilled in the northern part of Scotland, distinguishing it from other whiskey types. This designation contributes to Scotland's economic prosperity and is a tribute to its geographical diversity.
Step-by-step explanation:
The term that can only be legally applied to scotch distilled north of a line stretching from Greenock to Dundee is Highland. This region, known as the Scottish Highlands, is distinct from the Scottish Lowlands in both geography and legal designation for the production of scotch whiskey. The Highlands are known for their sweeping landscapes and, historically, for livestock production. In contrast, the Scottish Lowlands have been more favorable for agriculture. The Highland distinction for scotch whiskey gives it a unique character and status, contributing to the recognition and economic benefit of Scotland's largest export product.
Scotland's early adoption of shipbuilding and the subsequent overseas trade benefited from the prosperity of the Industrial Revolution and European colonialism, bolstering industries such as scotch whiskey production. The wealth collected from the North Sea's oil resources further supports Scotland's economic stability, which is impressive for its small population of around five million people.