# What's the special name for $N \rtimes \textrm{Aut}(N)$?

I was in class today, and the teacher mentioned that the semidirect product given by $$N \rtimes \textrm{Aut}(N)$$ has a special name, but I couldn't understand what he said well enough to write it down. Does anyone know what it's called, what it's useful for, and where I could learn more about it?

This type of semidirect product is the so-called holomorph of the group $$N$$ and (at least the name) was introduced by Burnside. Apparently (after a quick google search), the following problem/question is the origin of the holomorph: "Is it possible to include any given group as a normal subgroup in some other group so that all the automorphisms of $$N$$ are restrictions of inner automorphisms of this large group?"