What are single electron orbitals?

[dergu]

1. "i.e an electron is removed from one of the single electron orbitals into the vacuum."

I know what orbitals are but I don't know what constitutes single-electron orbitals. I first assumed it was simply an orbital which in a given configuration only had one electron but that had to be ruled out as the atom in question is a noble gas. I did a Course literature and Google search but I stand no wiser than before.

 

[dergu]

Is it maybe referring to the 1s2 2s2 orbitals as the two electrons have the same state with the exception of spin? If a mod feels this should be in advanced physics feel free to move :)