Explain why the square root of a number is defined to be

e qual to that number to the 1/2 power

The power of a number would be to the second power (^2)

to do the reciprocal of the power you need to use the fraction 1/2 in order to create a number that is lower than the number you started with.

1/2 power is the reciprocal of ^2 power (this is called squared)