A comprehensive glossary of stellar spectroscopy. Includes absorption lines, atoms and the chemical element,  chemical classes of stars, classifying stars, distances from spectra, double stars, electromagnetic spectrum, emission lines, interacting double stars, ions, isotopes, luminosity classes, molecules, planets, radiation by matter, radioactivity reflection, refraction, and dispersion, single-line double stars, spectral sequence, spectral classes, spectral sequence, the spectrograph, subdwarfs, velocities, visual spectrum