(archaeology, paleontology) The process by which individuals in a population die off in large numbers as part of a single event (rather than one by one, from a variety of causes).

(ornithology) A moult, typically in penguins, in which most or all of the feathers are shed at the same time / (zoology) A similar process in some seals in which large areas of skin are lost

(biology) The extinction of an organism (usually microorganisms) due to excessive RNA mutations.

(mathematics) The branch of mathematics dealing with dynamical systems which can undergo abrupt irreversible qualitative changes due to a tiny change in parameters.

(cosmology) The disagreement of over 100 orders of magnitude between measured values of the vacuum energy density and the theoretical zero-point energy suggested by a naïve application of quantum field theory.

plural of error catastrophe

(physics) A fault in classical physics, from the Rayleigh's Law/Rayleigh-Jeans Law outcomes at short wavelengths/high frequencies, that causes infinite amplification of shorter wavelength/higher frequency radiation inside a cavity, due to the application of equipartition theorem on black body radiation within a cavity.

An event during the oxygenation event of Earth's past, where the level of free oxygen in the environment exceeds the toleration levels of most extant anerobic life, becoming toxic to existing life, which prior to the mass production of oxygen, was an anerobic reducing environment. This is sometimes considered a mass extinction event, or the first mass extinction event, but as all life was unicellular, there is no fossil boundary to mark the event for conventional paleontology to recognize it.

A work of post-apocalyptic science fiction dealing with the adventures of a small group of people who survive the collapse of civilization relatively unscathed.

plural of cosy catastrophe