The property of the sound waves that determines the pitch of the sound is its

The pitch of a sound is primarily determined by its frequency, which is defined as the number of waves passing a given point per second [1]. The human brain associates specific musical pitches with these frequencies; higher frequencies result in higher-pitched sounds, while lower frequencies produce lower-pitched sounds [4]. For instance, a whistle has a higher frequency and pitch compared to a drum beat. In contrast, amplitude determines the loudness or volume of the sound rather than its pitch. While wavelength is inversely proportional to frequency, it is the frequency itself that is the direct physical property used to define pitch [2]. Therefore, the shrillness or depth of a sound is a direct consequence of the frequency of the vibrating source.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 15: Tsunami > Basics > p. 192
2. [3] https://www.nps.gov/subjects/sound/understandingsound.htm
3. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Explanation: > p. 279
4. [2] https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/doppler.html