The term 'Highland Boy' can be broken down into two crossword solutions: LAD (3 letters) and LADDIE (6 letters). The term 'LAD' is a British English term for a young boy, usually between the ages of 8 and 15. It is often used to refer to a young man from Scotland, especially from the Highlands. The term 'LADDIE' is a Scottish English term for a young man, usually between the ages of 16 and 25. It is often used to refer to a young man from Scotland, especially from the Highlands. Both terms are used to refer to a young man from Scotland, particularly from the Highlands.