Number of times the graph passes/sits/curls on the x axis. The minimum number of X intercepts varies. The maximum number of X intercepts will always be up the the Degree
Even degree polynomial
An even degree polynomial can have at least ZERO X Intercepts Because, not all graphs touch the x axis. it can be 0.
Additionally, it could cross the x axis all possible times. Degree times.
Odd degree polynomials
An odd degree polynomial has at least ONE X intercept. Cuz domain and range are all infinite.
And again, max is the Degree number of intercepts.