In this context, the term is just used to tell you to think in terms of pitch classes — where all notes that are separated by an integer multiple of an octave belong to the same class — and not expect actual Shepard tone trickery related to absolute pitch.

However, the relationship between absolute pitch and frequency isn't always trivial. The latter is a physical phenomenon, but the former is psycho-acoustic. When you have sounds with a normal set of overtones that align with a harmonic series, the perceived pitch matches the fundamental frequency. But that frequency doesn't actually need to be audible. By weighting the amplitudes of the partials in a certain way, you can also construct a sound that will be perceived as different pitches by different listeners, or by the same listener under different circumstances.

With sounds whose frequencies aren't all harmonic, assigning a pitch can get more complicated.