The name Douglas has its roots in the Scottish Gaelic language and culture, originating in the Middle Ages. It is derived from the Gaelic words "dubh" meaning "dark" and "glas" meaning "stream" or "water." The name can be interpreted as referring to a dark stream, river, or valley.

In its earliest form, the name was spelled as "Douglasce" or "Douglasse" and was associated with the Douglas clan, a powerful Scottish family that played a significant role in the nation's history. The first recorded use of the name dates back to the 12th century, with records mentioning a person named William de Douglasce in 1175.

The name gained prominence in the 13th and 14th centuries, thanks to the exploits of the Douglas clan and its members, such as Sir James Douglas, who was a close companion of Robert the Bruce and played a crucial role in the Scottish Wars of Independence against England in the early 14th century. Another notable figure was Archibald Douglas, Earl of Douglas, who was a powerful nobleman and military leader in the late 14th century.

Over the centuries, the name has been borne by several notable historical figures, including:

1. James Douglas, 4th Earl of Morton (c. 1516-1581), a Scottish nobleman and regent of Scotland during the minority of King James VI.
2. Stephen A. Douglas (1813-1861), an American politician and lawyer who famously debated Abraham Lincoln and was a leading figure in the Democratic Party before the Civil War.
3. Lord Alfred Douglas (1870-1945), an English poet and former lover of Oscar Wilde, whose infamous relationship led to Wilde's imprisonment.
4. Norman Douglas (1868-1952), a British novelist and travel writer best known for his novel "South Wind."
5. Donald Wills Douglas Sr. (1892-1981), an American aviation pioneer and founder of the Douglas Aircraft Company, which later merged with McDonnell Aircraft to form McDonnell Douglas Corporation.

The name has endured over the centuries, transcending its Scottish origins and becoming popular in various parts of the English-speaking world, particularly in the United Kingdom, the United States, and other countries with historical ties to the British Empire.