is: the range of different colours of light that make up white light. [P6.2]
can be seen: by allowing a beam of white light to undergo dispersion in a glass prism, or some similar optical device. [P6.2]
broadly corresponds: to different wavelengths in the approximate range 
to 
though the perception of colour by humans involves other factors. The different colours normally recognized (in the English language) within the visible spectrum (in order of decreasing wavelength) are red, orange, yellow, green, blue, indigo and violet. [P6.2]
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