A computer technology that simulates a real or imagined environment so that the user can interact with it as if physically present.

A check or review to make sure something is consistent, reasonable, etc. / (idiomatic) A wake-up call, reminder.

(humorous, euphemistic, of a person) Crazy, bonkers, insane.

(television) A genre of television programming portraying one or more people who are not professional actors and depicting their reactions to given stimuli or goals.

Alternative form of reality television

(computing) The merging of a view of the real-world environment upon a digital image in real time.

(psychology, psychoanalysis, Freudianism, often hyphenated when used attributively) The mental mechanism which guides a person, as he or she matures, in adapting to and coping with the real, external world, by suppressing or deferring the childish gratification-seeking desires of the id.

Reality, the real world, that which is not virtual nor augmented nor an online world

The merging of real and virtual worlds to produce new environments and visualizations where physical and digital objects coexist and interact.

The psychotherapeutic technique of reflecting on the objective or real world and one's relationship to it, so as to distinguish the internal world of thoughts and feelings from the external world.