In a polynomial expression, the constant term is the term that does not contain a variable. It is a term that has a fixed value, or a coefficient that is not multiplied by any variable. For example, in the polynomial expression 4x^2 + 3x - 2, the constant term is -2. The constant term represents a fixed value or a y-intercept on a graph of the polynomial. It is the value of the polynomial when x is equal to zero. In other words, the constant term is the value of the polynomial when there are no x terms present.