square root Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a number that produces a specified quantity when multiplied by itself. Example Sentence Two is the square root of four. More Example Sentences Finding the square root can be easy. Synonyms radical; root Antonyms 3 x 5 equals 15 Hear It! Say It! Write It! square root Switch to cursive Start Share with your friends: