noun

• (mathematics, arithmetic) The process of calculating a power by multiplying together a number of equal factors, where the exponent specifies the number of factors to multiply.
  "In 5⁴ the base is 5 and the power is 4, so there are 4 identical factors of 5, and exponentiation gives 625 as the result."
• (mathematics, arithmetic, countable) A mathematical problem involving exponentiation.
  ""The remarkable fact about the system is that it achieves such a high level of security with only six exponentiations," Boneh said, referring to the calculations used to raise numbers to a power. Other systems do exponentiation once, suggesting that this system may be about six times slower because exponentiation is the most time-consuming step in encrypting the data."