Frequency refers to the number of complete cycles of a sound wave that occur in one second and is measured in hertz (Hz). It determines the pitch of the sound, with higher frequencies corresponding to higher-pitched sounds. Amplitude, on the other hand, refers to the maximum displacement of particles in the medium from their equilibrium position during the passage of a sound wave. It is related to the intensity or loudness of the sound, with larger amplitudes corresponding to louder sounds.