An Etymological Dictionary of Astronomy and Astrophysics

Emission nebulae: The relative amount of a given → chemical element in an ionized nebula with respect to another element, usually → hydrogen. Elemental abundance ratios of → emission nebulae are obtained either by adding the observed → ionic abundances of the element or by using → ionization correction factors. Same as → total abundance.

See also: Elemental, from M.L. elementalis, → element

• -al;
  abundance, from O.Fr. abundance, from L. abundantia “fullness,” from abundare “to overflow,” from L. ab- “away” + undare “to surge,” from unda “water, wave;” → abundance.