Glossaire beginning with C

Coma

Gas and dust cloud surrounding the nucleus of a comet.

Constellation
Imaginary figure (mythological being, animal, instrument, etc.) used as a mnemonic device to locate the position of the stars. Constellations are now defined as parts of the sky roughly bounded by portions of celestial parallels and meridians.
Continuous spectrum
Emission or absorption covering a wide wavelength range without preferred wavelength.