The term liminal derives from the Latin, limins, and refers to the threshold passageway between two separate places. The liminal state is a transitional one, the result of crossing a threshold between locations, status, position, mental state, social condition, war and peace, or illness and death. In early written use, liminal, referred to something (such as a physical stimulus) which was perhaps just barely perceptible, or just barely capable of eliciting a response.

The word limin refers to the point at which a physiological or psychological effect begins to occur.

In its most common extended meaning today, it describes a state, place, or condition of transition, as in “the liminal zone between sleep and wakefulness.”

The closely related word subliminal means “below a threshold”; it can describe something inadequate to produce a sensation or something operating below a threshold of consciousness.