| E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898. |
| | | Spectrum, Spectra, Spectre (Latin, specto, to behold). | | |
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In optics a spectrum is the image of a sunbeam beheld on a screen, after refraction by one or more prisms. Spectra are the images of objects left on the eye after the objects themselves are removed from sight. A spectre is the apparition of a person no longer living or not bodily present. | 1 |
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