spectrum
/ˈspektrəm/noun
(pl. spectra /-trə/)
1
- a band of colours, as seen in a rainbow, produced by separation of the components of light by their different degrees of refraction according to wavelength谱, 光谱。
1.1
- (the spectrum) the entire range of wavelengths of electromagnetic radiation波谱。
1.2
- an image or distribution of components of any electromagnetic radiation arranged in a progressive series according to wavelength电磁波谱。
1.3
- a similar image or distribution of components of sound, particles, etc., arranged according to such characteristics as frequency, charge, and energy频谱。
2
- used to classify something, or suggest that it can be classified, in terms of its position on a scale between two extreme or opposite points范围：
the left or the right of the political spectrum.
政治领域里的左派和右派。
2.1
- a wide range大范围; 大幅度：
self-help books are covering a broader and broader spectrum.
指导自己动手的书籍涉及越来越广的范围。
词源
early 17th cent. （in the sense 'spectre'）： from Latin, literally 'image, apparition', from specere 'to look'.