Light of a single wavelength.

All objects in a group(electrons, light, X-rays....etc.) have the same energy/wavelength.

an image that contains a single band, which is rendered in grayscale

(of light or other electromagnetic radiation) having only one wavelength; "monochromatic light"

Said of a beam of photons when the bandwidth of the photons is so narrow that all the photons essentially have the same wavelength. This is one of the defining characteristics of a laser beam.

An image consisting of shades of one single colour. Technically light consisting of one single wavelength.

measured at a single wavelength (or frequency). The units depend on whether we are using wavelength or frequency: monochromatic flux on a wavelength scale is measured in W m-2 nm-1, whereas on a frequency scale the units are W m-2 Hz-1.

Consisting of a single wavelength or narrow range of wavelengths. (See spectral light.)

Pertaining to a single wavelength or, more commonly, to a narrow band of wavelengths.

Of or pertaining to a single wavelength, or in practice, perhaps a very narrow spectral interval.

Consisting of radiation or rays, such as ultraviolet rays, of a single wave length or of a very small range of wave lengths.

A light that consists of only one wavelength. An industrial laser beam consists of a very narrow band of wavelengths around a central wavelength.