roundlet
/ˈraʊndlɪt/noun
1A small round or circular object; a round or circular piece of something; something formed into a small circle or ring.
2A medieval headdress resembling a turban, made of a thick circular roll of material. historical.
3 Heraldry. = roundel. Now rare.
Origin
Late Middle English. Partly from round + -let (in sense 1a probably after Anglo-Norman rondelet and Middle French rondelet (adjective) somewhat round or rounded, (noun) small round ornament; senses 1b and 1c are not paralleled in French), and partly from Middle French rondelet short rondeau or roundel.