Square Root

The Square Root at U+221A is a mathematical operator that marks the principal square root of a number or expression. It is part of the Mathematical Operators block and is commonly read aloud as “the square root of,” as in √9 = 3. Its main use is in arithmetic, algebra, geometry, physics, and engineering formulas. In school and professional notation, √x means the nonnegative value whose square is x, while an extended radical bar may cover a larger expression such as √(a² + b²) in plain text or typeset form. It appears in the quadratic formula, distance formulas, standard deviation calculations, circuit analysis, and many other places where roots are needed. The symbol is also used in calculators, spreadsheets, educational software, and technical writing as the recognizable square-root key or operator. For cube roots and higher roots, mathematics usually adds a small index to the radical, such as ³√8, rather than changing the basic sign. A practical distinction is that √ is not the same character as the check mark, even though casual handwriting or some fonts can make them look related. In searchable or copied mathematical text, using the actual square root sign helps distinguish a radical expression from an approximation, a tick mark, or a decorative check.