"Percent" comes from the Latin Per Centum. The Latin word Centum means 100, for example, a Century is 100 years.
History of Percentage?
In Ancient Rome, long before the existence of the decimal system, computations were often made in fractions in the multiples of 1/100 For example, Augustus levied a tax of 1/100 on goods sold at auction known as centesimal Rerum valium. Computation with these fractions was equivalent to computing percentages.
As denominations of money grew in the Middle Ages, computations with a denominator of 100 became increasingly standard, such that from the late 15th century to the early 16th century, it became common for arithmetic texts to include such computations. Many of these texts applied these methods to profit and loss, interest rates, and the Rule of Three. By the 17th century, it was standard to quote interest rates in hundredths.