root
"Root" is a wonderfully versatile word with several important meanings. Most people know it from plants, but it also appears in mathematics, language, and everyday expressions. Here are the most common and useful senses.
In mathematics, the root of a number is another number that, when multiplied by itself, gives you the original number. For example, the square root of 9 is 3, because 3 × 3 = 9.
mathematics · Modern, widely used