The wavelength of the third harmonic depends directly on the propagation velocity of the wave medium and is mathematically equal to the fundamental wavelength divided by three. In a physical system like a vibrating string fixed at both ends or an acoustic open pipe, the third harmonic represents a standing wave pattern containing three half-wavelengths across the total length of the medium. Because wavelength is inversely proportional to frequency, as the frequency increases to three times the fundamental baseline, the corresponding spatial wavelength contracts to one-third of its original length, creating shorter nodes and antinodes within the physical propagation boundary.