The term 'Old British Soldier' can be summarized as a Redcoat, which is a seven-letter word. Redcoats were the nickname given to the British soldiers who served in the British Army during the 18th and 19th centuries. They were known for their bright red uniforms, which made them easily recognizable on the battlefield. Redcoats fought in many wars, including the American Revolutionary War, the Napoleonic Wars, and the War of 1812.