For the Hilbert scheme of points $\operatorname{Hilb}^n_d$ we define the smoothable component $Smbl^n_d$ to be the closure of the "locus of smooth subschemes". But what exactly is this locus? Does it only contain those closed points $[R]$ of $\operatorname{Hilb}^n_d$ such that $R$ is smooth? Or does it also contain some other points which are not closed? I am confused about the term "locus" here.
Many thanks.