Definition:Root of a Polynomial
From ProofWiki
Definition
Let $R$ be a commutative ring with unity whose zero is $0_R$ and whose unity is $1_R$.
Let $f \left({x}\right)$ be a polynomial function in $x$, where $x \in R$.
Then the values of $x$ for which $f \left({x}\right) = 0$ are known as the roots of the polynomial $f$.