noun
/ˈspɛktrəm/ , pl spectra /ˈspɛktrə/ or spectrums
[count] the group of colors that a ray of light can be separated into including red, orange, yellow, green, blue, indigo, and violet :the colors that can be seen in a rainbow
b technical :an entire range of light waves, radio waves, etc.
a complete range of different opinions, people, etc.