Of, or pertaining to, spectres; ghostly. / Of, or pertaining to, spectra; classified according to frequency or wavelength (of light etc)

(physics) An electronic device that displays the frequency spectrum of an electrical, optical or acoustic waveform.

(idiomatic) Needs for special care, services or accommodations for disabilities.

The colours of the rainbow. / (physics) The distribution of colours produced when white light passes through a prism. / (astronomy, physics) The range of frequencies of visible light.

(physics) The entire range of wavelengths of all known electromagnetic radiations extending from gamma rays, to X-rays through visible light, infrared, to radio waves.

(numismatics) A banknote printed for distribution to central banks to aid in the recognition of banknotes from a country other than their own

An explicit set of requirements to be satisfied by a material, product, or service. / An act of specifying.

For a special purpose, person, or occasion. / (proscribed) extremely / (proscribed) in particular

A breakfast cereal made primarily from rice and wheat.

(slang) Ketamine, used as a hallucinogen.