I use this term to denote a set of numbers of the form $\sum z_n x^n$, where $x$ is the solution of some polynomial $x^a=\sum z_ix^i$ for $i=0$ to $a-1$.
$a$, $i$, and the $z_j$ are all in $\mathbb{Z}$.
For example, “the span” of $a^3=7$ would be all numbers of the form $xa^2+ya+z$, $x,y,z\in\mathbb{Z}$, where $a^3=7$.
Is there a standard term for it?