The word pure tone is used in different ways. For some it means that the sound wave is a perfect or continuous line. For others it means that the frequency of the wave is constant. In all cases, pure tones can be represented by a graph with frequency (horizontal axis) on the y-axis and intensity (vertical axis) on the x-axis. The diagram below illustrates the pitch of a pure tone as a function of frequency.

For most listeners, pure tones are just plain old boring. There's nothing particularly exciting or beautiful about a steady roar of sound reaching your ear at a specific frequency.