In medieval France the first-born sons of nobility were known as the “caput,” or head, of the family.
While the younger, less valuable boys were called “capdets,” or little heads, and were often sent to the military to train as officers.
In English, “capdets” became “cadets,” which the Scots abbreviated to “cads” or “caddies,” meaning any useless street kid who could be hired for the day to carry around a bag of golf clubs.
Golf assistants are still commonly called “caddies”.
