three concentric circles; triple circle
Refers to a symbol consisting of three concentric circles, often used as a mark of excellence or highest grade in Japanese grading systems.
I got a triple circle on the test.
The triple circle on this document means the highest evaluation.
Compound of 三 (three), 重 (layer, fold), and 丸 (circle). The reading さんじゅうまる follows standard on'yomi for the first two kanji and kun'yomi for 丸.