root

ROOT noun

[ C ] uk/ruːt/ us root noun [C]
(HAIR/TOOTH)

the part of a hair or tooth that is under the skin

корень
 the root of sth
the cause of something, usually something bad

причина, источник чего-либо
the root of all evil Смотрите такжеgrass root s The root of a particular number is another number which, when multiplied by itself one or more times, equals the first number.

(математический) корень
Смотритеsquare root cube root