Definition
A roundel is a circular disc or panel, often used for decorative purposes. Think of it as a fancy button ⚪ or a small shield 🛡️. It can be found in architecture, heraldry, or even aviation. In architecture, it might be a circular window or a decorative panel. In heraldry, it's a circular charge on a coat of arms. Unlike a square or rectangle, a roundel's defining feature is its circular shape.