A circlet is a thin band, often of gold, silver, or jewels, worn as an ornament around the head — like a very small, light crown — or sometimes around the arm. It is a dress-and-story word more than a street word: you meet it in fairy tales, museum labels, wedding jewellery, and fantasy books. A full crown is heavier and says “I rule”; a circlet is narrower and often says “this is pretty” or “this is for a ceremony.” Though actually, in older times a simple metal band around the head could also mark rank, so the line between circlet and small crown is not always tidy. It is not just any little circle (a ring on a finger is not a circlet). The shape is a circle, but the point is that you wear it as a band.

細冠、頭環（窄的金屬或珠寶箍，戴在頭上或臂上）