What's the difference? From what I'm reading online geometric is just the discrete version of exponential

No difference, you’re right. I meant polynomial not geometric. :P

geometric/polynomial: x^2, x^3, etc

exponential: 2^x, 3^x, etc

Everything in the second group eventually grows faster than everything in the first group, no matter how small and big you make the fixed numbers, so they are two different classes.

Geometric is exponential; I goofed above. Geometric and exponential are sometimes used interchangeably, but sometimes people use geometric to refer to discrete intervals and exponential to refer to continuous functions.