The term "Alexander Selkirk" refers to a real person, a Scottish sailor who lived in the 17th and early 18th centuries. Here’s a simple explanation and breakdown of the term for a new English learner:
Alexander Selkirk (noun): A Scottish sailor who was left alone on a deserted island near Chile for five years. His experiences inspired the famous novel "Robinson Crusoe" written by Daniel Defoe.
In summary, "Alexander Selkirk" is a historical figure whose life story of isolation and survival has had a lasting impact on literature.