ˈspektrəm n. (pl. spectra) 1
the band of colours, as
seen in a
rainbow etc., arranged in a
progressive series according to
their refrangibility or
wavelength. 2 the
entire range of wavelengths of
electromagnetic radiation. 3 a an
image or
distribution of parts of electromagnetic radiation arranged in a progressive series according to wavelength. b
this as
characteristic of a
body or
substance when emitting or
absorbing radiation. 4 a
similar image or distribution of
energy, mass, etc., arranged according to
frequency,
charge, etc. 5 the entire range or a
wide range of
anything arranged by
degree or
quality etc. 6 (in full
ocular spectrum) an after-image. øspectrum (or spectral)
analysis chemical analysis by
means of a
spectroscope. [L, = image,
apparition f. specere look]