tondo
noun
ton·do ˈtän-(ˌ)dō 
plural tondi ˈtän-(ˌ)dē
1
: a circular painting
2
: a sculptured medallion
Example Sentences
Recent Examples on the Web The exhibition includes five rectangular and two tondo (round) paintings. 
Danielle Avram, Dallas News, 12 Nov. 2020 Created around 1480, the canvas depicts a handsome young man with a small tondo of a saint in his hands. Katya Kazakina, Bloomberg.com, 7 Oct. 2020 DeLap began slicing up the traditional rectangle — as well as the less common (but equally traditional) circular tondo — into various irregular geometries. Christopher Knight, latimes.com, 16 Mar. 2018
Danielle Avram, Dallas News, 12 Nov. 2020 Created around 1480, the canvas depicts a handsome young man with a small tondo of a saint in his hands. Katya Kazakina, Bloomberg.com, 7 Oct. 2020 DeLap began slicing up the traditional rectangle — as well as the less common (but equally traditional) circular tondo — into various irregular geometries. Christopher Knight, latimes.com, 16 Mar. 2018 Word History
Etymology
Italian, from tondo round, short for rotondo, from Latin rotundus — more at rotund
First Known Use
1890, in the meaning defined at sense 1