Which term refers to the material through which a wave travels?

The term that refers to the material through which a wave travels is "medium." In physics, a medium can be any substance that can support the propagation of a wave, such as air, water, or solid materials. For example, sound waves travel through air, while water waves travel through water. The characteristics of the medium can greatly influence the speed and behavior of the wave as it propagates through that medium.

Waveform refers to the shape of the wave as it travels, but it does not describe the material itself. Amplitude is a measure of the height of the wave, indicating the energy of the wave, while frequency relates to how many wave cycles occur in a specific time period. These terms describe different properties of waves but do not define the substance through which the wave is moving. Thus, the correct term for the material through which a wave propagates is indeed "medium."