Roundel

Part of speech: noun (n.)

1. A rondelay. "Sung all the roundel lustily." Chaucer. Come, now a roundel and a fairy song. Shak.

2. Anything having a round form; a round figure; a circle. The Spaniards, casting themselves into roundels, . . . made a flying march to Calais. Bacon. Specifically:

3. A small circular shield, sometimes not more than a foot in diameter, used by soldiers in the fourteenth and fifteenth centuries.