# square root

## English

### Noun

square root (plural square roots)

1. English Wikipedia has an article on:
Wikipedia
The number which, when squared, yields another number.
The square roots of 4 are 2 and −2, the square root of 0 is 0, and the square roots of −4 are 2i and −2i.
• a. 1992, Frederick Mosteller, “Writing about Numbers”, in John C. Bailar III, Frederick Mosteller, editors, Medical Uses of Statistics[1], second edition, published 1992, page 388:
In √a̅+̅b̅, the horizontal bar or vinculum is actually a parenthesis that groups a+b. Without it, √a+b might mean b+√a̅ or it might mean √a̅+̅b̅. Nevertheless, the square-root sign without the vinculum is often used [] .
2. The positive number which, when squared, yields another number; the principal square root.
The square root of 4 is 2. No negative real square roots exist. Negative numbers have no real square roots.

#### Usage notes

Even in mathematical contexts, square root generally means positive square root. If there is a chance of ambiguity, prefer constructions like a square root or a complex square root to indicate the first definition, or the positive square root or similar to indicate the second sense.