What does a polynomial with only one term signify?

A polynomial with only one term is referred to as a monomial. This means that it can be expressed in the form of a single term that consists of a variable raised to a non-negative integer power, potentially multiplied by a coefficient. For example, 3x^2 and -5 are both considered monomials.

In contrast, other terms in the options refer to different types of polynomials. A constant term represents a number without any variable and is a specific instance of a monomial where the variable's exponent is zero. A binomial consists of exactly two terms, while a quadratic expression specifically involves terms of degree two (the highest power of the variable being squared). Therefore, a polynomial with only one term distinctly classifies it as a monomial, making this the correct choice.