The story
From poly- + -nomial, from νομός (nomós, “portion, part”), by analogy with binomial.
Etymology from Wiktionary, CC BY-SA 4.0.
polynomial
Today it means: An expression consisting of a sum of a finite number of terms, each term being the product of a constant coefficient and one or more variables raised to a non-negative integer power, such as a_nxⁿ+a_n-1xⁿ⁻¹+...+a_0x⁰. Full definition →