A wave with no frequency and no wavelength is called a DC (Direct Current) or a constant voltage. In the context of electromagnetic waves, which typically have a frequency and wavelength, a wave without frequency and wavelength refers to a constant or steady signal that does not vary over time. Instead of oscillating or propagating as a wave, a DC signal remains at a constant value. It is often represented by a straight horizontal line on a graph, indicating a consistent voltage or current level. DC signals are commonly used in electronic circuits and power systems.