The example given here is a binomial, meaning that the variable is raised to two different powers (x and x2). Mathematicians say that this polynomial has two terms. If there were another variable, each power that that second variable was raised to would be a different term.
A one–term polynomial is called a monomial, and a three–term polynomial is called a trinomial. The term "quadrinomial" is occasionally used for a four–term polynomial.
© Haydn Thompson 2017