Blighty is a British English slang term for Britain, deriving from the Hindustani word vilāyatī (विलायती) (pronounced bilāti in many Indian dialects and languages), from Persian vilayet and ultimately from Arabic wilayah, originally meaning something like "province". In India the term came to refer to Europe, and more specifically Britain.

The term was more common in the latter days of the British Raj, and is now more commonly used as a term of endearment by the expatriate British community or those on holiday to refer to home.

In their 1886 Anglo-Indian dictionary, Hobson-Jobson, Sir Henry Yule and Arthur C. Burnell explained that the word came to be used in British India for several things the British had brought into the country, such as the tomato (bilayati baingan, whose literal translation is "foreign aubergine") and soda water, which was commonly called bilayati pani ("foreign water").

During World War I, "Dear Old Blighty" was a common sentimental reference, suggesting a longing for home by soldiers in the trenches. The term was particularly used by World War I poets such as Wilfred Owen and Siegfried Sassoon. During that war, a Blighty wound — a wound serious enough to require recuperation away from the trenches but not serious enough to kill or maim the victim—was hoped for by many, and sometimes self-inflicted.