The square root of 25 is 5. This means that 5 multiplied by itself (5 x 5) equals 25. The concept of square roots is fundamental in mathematics, representing a value that, when squared, gives the original number. Square roots can be both positive and negative, but generally, when referring to square roots, the positive root (known as the principal square root) is considered. Square roots are commonly encountered in algebra, geometry, and various applications in science and engineering.