‘圆规’ is a two-character noun referring to the drawing tool used to draw circles and arcs—what English speakers call a ‘compass’. The first character, 圆 (yuán), means ‘circle’ or ‘round’, indicating the primary function of the tool; the second character, 规 (guī), means ‘instrument for measuring or drawing’, often appearing in words related to tools or standards (e.g., 规则 ‘rule’, 规矩 ‘standard’). Together, they literally mean ‘circle-drawing instrument’.

This word is commonly used in school settings, technical drawing, geometry classes, and art supplies contexts. It’s a standard term in both spoken and written Mandarin—not slang or dialectal—and appears frequently in textbooks, stationery catalogs, and classroom instructions. Unlike some compound nouns where characters may shift meaning, 圆规 retains its literal, transparent composition, making it relatively easy to remember for learners who know the individual characters.