plural of external world

(marketing) The situation where a potential consumer looks for the best good or service in an unfamiliar, expensive, or infrequently-bought category, requiring a great deal of research.

plural of extended household

Alternative form of age of extinction

plural of extinction event

plural of mass extinction event

The current period of Earth history characterised by large-scale extinction of lifeforms as a result of human activity.

(evolutionary theory, geology) One of five historical events in which the Earth experienced a loss of ∼75% of all species over a geological interval of less than 3 million years, the most recent being the Cretaceous–Paleogene extinction event 66 million years ago.

Assignments offered as a way to gain points, typically in a class, that are not mandatory to complete.

(electronics, UK) extension cord