Characteristics of waves in plasmas are introduced based on the dispersion relation of the waves. They are interpreted over a wide area of frequencies, i.e., from below the ion cyclotron frequency to above the electron cyclotron frequency and over a wide range of electron densities of order 1010. These characteristics are summarized in a Clemmow-Mullaly-Allis (CMA) diagram, whose abscissa and ordinate are a normalized electron density, i.e., (Πe/ω)2, and a normalized electron cyclotron frequency, i.e., (Ωe/ω)2, respectively. Minority ion cyclotron range of frequency heating is discussed using the dispersion relation.