In the context of electron orbitals, what does the designation '3p' refer to?

The designation '3p' refers specifically to the third energy level of electron orbitals. In atomic structure, the principal quantum number indicates the energy level of an electron within an atom. The number preceding the letter 'p' in this designation, which is '3', indicates this is the third energy level. The 'p' denotes the type of orbital which has a specific shape and can hold a maximum of six electrons. This is why '3p' is associated with the third energy level in atomic theory, distinguishing it from the first, second, or fourth energy levels, which would be indicated by the labels '1s', '2p', or '4d', respectively.