The leading coefficient of a polynomial is the coefficient of the monomial term with the greatest degree that has a nonzero coefficient.

For a generic polynomial in x,

anxn + an-1xn-1 + ... a1x + a0, where n is the largest nonnegative integer such that an is not equal to 0,

the leading coefficient is an. If the leading coefficient is equal to 1, then the polynomial is monic.