tondo - A painting in the shape of a circle.
Most often found in Italian Renaissance painting, and in paintings of Madonnas. Raphael and Sandro Botticelli painted several tondos.
Examples:
Sandro Botticelli (Italian, 1445-1510), Madonna of the Magnificat, c.1485, tempera on wood panel, diameter 118 cm, Uffizi, Florence.
Sandro Botticelli, Madonna of the Pomegranate, Madonna and Child and six Angels, c. 1487, Uffizi, Florence.
Italian (Siena?), Mirror Frame, c. 1490-1500, carved and gilt poplar, height 24 1/4 inches (61.6 cm), width 13 7/8 inches (35.2 cm), diameter circle 6 inches (15.2 cm), Metropolitan Museum of Art, NY. See frame and mirror.
Filippino Lippi (Italian, c. 1457-1504) The Holy Family with John the Baptist and St. Margaret, c. 1495, oil and tempera on wood (poplar) panel, diameter 153 cm, Cleveland Museum of Art.
Circle of Fra Bartolommeo (Italian, Florence, 1472-1517), possibly Mariotto Albertinelli, Madonna and Child with Saints and Angels, c. 1510, oil on wood panel, Columbia Museum of Art, SC.
Michelangelo Buonarotti (Italian, 1475-1564), The Holy Family with the infant St. John the Baptist (the Doni Tondo), c. 1503-05, oil on wood panel, diameter 47 inches (120 cm), Uffizi, Florence.
Raphael (Raffaello Sanzio) (Italian, 1483-1520), Madonna and Child (Madonna Conestabile), 1502/3, tempera on canvas (transferred from panel), 7 x 7 inches (17.5 x 18 cm), State Hermitage Museum, St. Petersburg, Russia.
Also see curve, kaleidoscope, mandala, and rondel.
https://inform.quest/_art