Ullswater is the name of a lake in the Lake District, in the northwest of England. It is a proper noun, so it always takes a capital U and never takes 'the' — you go to Ullswater, you sail on Ullswater, not 'the Ullswater'. It is the second largest lake there, long, narrow and curved, running between steep hills, and it is one of the best known because of the walking and the boats. The name is worth a moment: most of the lakes in that area are called 'mere' or 'water' rather than 'lake' — Windermere, Grasmere, Ullswater, Derwentwater — which is why English speakers find 'Lake Windermere' slightly odd, and why there is a well-worn local joke that the Lake District contains only one actual 'lake' (Bassenthwaite Lake). For a student, the useful lesson is not the geography but the pattern: British place names often hide old words for the land, and 'water' here is one of them.

阿爾斯沃特湖，英格蘭西北部湖區（Lake District）的湖泊之一。台灣中文常直接音譯「阿爾斯沃特湖」，或說「英國湖區的湖」。注意英文名稱本身不帶 lake 一字。