How to classify a function constant linear quadratic cubic quartic?

It's constant when it contains no variables (x) , linear when the variable(x) is from first degree (power = 1), quadratic when the variable is from second degree (power = 2) , cubic when the variable is from third degree (power = 3), quatric when the variable is from forth degree (power = 4)

The first digit is in the middle school 100s place