Crossword Dictionary

roundel 

roundel, roundels, roundle - n 
a round figure or object 

wordplays

synonyms 

circle, cirque, ring, round

in a sentence 

the windows in the colonial-era statehouse are roundels

So far researchers have been able to excavate much of the roundel itself.

One iconic roundel is the Goseck Circle, an ancient observatory found in Germany.

merriam-webster

etymology 

c. 1300, "a circle, anything round;" early 14c., "a round slice;" from Old French rondel, rondeaul"round dance; dance lyric; roundel," from rond "round" (see round (n.)). From late 14c. as "an ornamental ball or knob;" also "a short poem on two rhymes."

etymonline.com

heraldry

A roundel is a circular disc used as a symbol. The term is used in heraldry, but also commonly used to refer to a type of national insignia used on military aircraft, generally circular in shape and usually comprising concentric rings of different colours. Other symbols also often use round shapes.  

wikipedia