The degree of a polynomial in one variable is the highest power of the variable among its various terms.
Also, a polynomial is named according to the number of terms it contains.
Hence,
100x2 is a monomial as it has only one term.
x99+4 is a binomial as it has two terms only.
x7+4x+9 is a trinomial as it has three terms.
x3+4x2+9x+2 is a cubic polynomial as its degree is 3.