In mathematics, the degree of a polynomial is the highest of the degrees of the polynomial's monomials (individual terms) with non-zero coefficients. The degree of a term is the sum of the exponents of the variables that appear in it, and thus is a non-negative integer. For a univariate polynomial, the degree of the polynomial is simply the highest exponent occurring in the polynomial. The term order has been used as a synonym of degree but, nowadays, may refer to several other concepts (see Order of a polynomial (disambiguation)).
For example, the polynomial which can also be written as has three terms. The first term has a degree of 5 (the sum of the powers 2 and 3), the second term has a degree of 1, and the last term has a degree of 0. Therefore, the polynomial has a degree of 5, which is the highest degree of any term.
To determine the degree of a polynomial that is not in standard form, such as , one can put it in standard form by expanding the products (by distributivity) and combining the like terms; for example, is of degree 1, even though each summand has degree 2. However, this is not needed when the polynomial is written as a product of polynomials in standard form, because the degree of a product is the sum of the degrees of the factors.
The following names are assigned to polynomials according to their degree:
Special case – zero (see , below)
Degree 0 – non-zero constant
Degree 1 – linear
Degree 2 – quadratic
Degree 3 – cubic
Degree 4 – quartic (or, if all terms have even degree, biquadratic)
Degree 5 – quintic
Degree 6 – sextic (or, less commonly, hexic)
Degree 7 – septic (or, less commonly, heptic)
Degree 8 – octic
Degree 9 – nonic
Degree 10 – decic
Names for degree above three are based on Latin ordinal numbers, and end in -ic. This should be distinguished from the names used for the number of variables, the arity, which are based on Latin distributive numbers, and end in -ary. For example, a degree two polynomial in two variables, such as , is called a "binary quadratic": binary due to two variables, quadratic due to degree two.