the highest way of classing an electron, contains many subshells. Labelled with 1, 2, 3, 4, 5 etc.
a group of orbitals with particular properties like shape and angular momentum. Labelled s, p, d, f, g etc.
can contain up to two electrons and has a particular shape and orientation.
e.g. is the z-aligned orbital in the p subshell in the second shell.