SPECTRUM

noun (plural spectra or ~s) see: specter Date: 1671 1. a continuum of color formed when a beam of white light is dispersed (as by passage through a prism) so that its component wavelengths are arranged in order, any of various continua that resemble a color ~ in consisting of an ordered arrangement by a particular characteristic (as frequency or energy): as, electromagnetic ~ , radio ~ , the range of frequencies of sound waves, mass ~ , the representation (as a plot) of a ~, 2. a continuous sequence or range , kinds of organisms associated with a particular situation (as an environment), a range of effectiveness against pathogenic organisms