Compound interest is the interest calculated on the initial principal and also on the accumulated interest of previous periods. It is commonly used in finance and investments to calculate growth over time.
Exponential Growth: Growth whose rate becomes ever more rapid in proportion to the growing total number or size.
Principal: The initial sum of money placed in an account or invested.
$e$ (Euler's Number): $e$ is a mathematical constant approximately equal to 2.71828, used as a base for natural logarithms and continuous compounding.