An Etymological Dictionary of Astronomy and Astrophysics

1. Dimming of light by an intervening medium (the Earth’s atmosphere or the interstellar medium). It is usually due to both scattering and absorption.
   
2. Paleontology: The act or process of dying out or coming to an end, becoming extinct: the extinction of a species; → mass extinction.

Etymology (EN): Noun of extinct, from L. extinctus, p.p. of extinguere “to quench, wipe out,” from → ex- “out” + stinguere “to quench,” from PIE base *steig- “to prick, stick, pierce;” cf. Mod.Pers. tiz, tež, tig, tej, tij, tiq
“sharp;” Av. tiγra- “pointed,” tiγray- “arrow;” → deblur.

Etymology (PE): Xâmuši, noun of xâmuš “extinguished; silent,” Mid.Pers. xâmôš “silent;” cf. Skt. amrs- “to bear patiently.”