In astronomy, the dimming of starlight as it passes through the interstellar medium. Dust scatters some of the light, causing the total intensity of the light to diminish. It is important to take this effect into account when measuring the apparent brightness of stars. The dark bands running across portions of the Milky Way in the sky are due to extinction by copious amounts of dust in the plane of our galaxy.

In paleontology and biology, the permanent disappearance of a species after all individuals have died off.

Some or all content above used with permission from J. H. Wittke.