Pitch can be described as a subjective perception of an auditory stimulus which cannot be objectively, unambiguously quantified. It is strongly related to the objective physical property of frequency such that higher frequencies typically correspond to higher perceived pitch, but even notes with identical frequency can be perceived as having different pitches, depending on how loud they are, what other frequencies are played at the same time or in close proximity, and other factors. A pure sine wave is usually fairly easily mapped to its perceived pitch, but more complex sounds may not be.
A mixture of many frequencies may have a dominant frequency which is perceived as the overall pitch of the sound, or the many frequencies may mix in a way that are not perceived as any particular pitch at all. The sound of a snare drum, for example, is not usually perceived as having any particular pitch, but almost everyone would agree that a snare drum has a higher pitch than a bass drum. 362
The bass drum resonates more strongly with lower frequencies than the snare drum does, but neither sound is very well described as having a particular pitch.
You may be interested in auditory illusions like the <PERSON>–Risset glissando, which is perceived as having ever-ascending pitch, despite the fact that the frequencies remain within a fixed window. We can objectively quantify the underlying frequencies, but it is not always simple to map a waveform to the subjective experience of pitch. As pointed out by <PERSON>, it's even possible to perceive a pitch from a complex tone when the corresponding frequency is damped or even completely absent from the waveform. The pitch produced by a timpano, for example, is implied by the harmonics it produces, with the fundamental frequency resonating much more weakly than higher frequencies - the perceived pitch of the drum is not simply the frequency with the highest amplitude. Practical applications of this effect can be seen in the design of some sound systems that have small speakers - by using a particular combination of higher frequenies, it allows the listener to experience low pitches that the speaker is not even physically capable of producing! 40