An exteriorisation of the consciousness out of the body. Part of the consciousness, mental, vital or subtle physical or all together rises out of the body, leaving it in a strongly internalised condition, sleep or trance and can move about alone in other planes or in the room and outside on the earth plane. In such cases the body can be seen as lying below or in the room, seen clearly as one sees a separate object with the physical eyes. A fear such as you had can come in these exteriorisations and bring the consciousness back with a rush to the body.

There is a continuous scale of the planes of consciousness, beginning with the psychical and other belts attached to and dependent on the earth plane and proceeding through the true independent vital and psychical worlds to the worlds of the gods and the highest supramental and spiritual planes of existence. And these are in fact always acting upon our subliminal selves unknown to our waking mind and with considerable effect on our life and nature. The physical mind is only a little part of us and there is a much more considerable range of our being in which the presence, influence and powers of the other planes are active upon us and help to shape our external being and its activities.

As if from Matter's plinth and viewless base
To a top as viewless, a carved sea of worlds
Climbing with foam-maned waves to the Supreme
Ascended towards breadths immeasurable;
It hoped to soar into the Ineffable's reign:
A hundred levels raised it to the Unknown.
So it towered up to heights intangible
And disappeared in the hushed conscious Vast
As climbs a storeyed temple-tower to heaven
Built by the aspiring soul of man to live
Near to his dream of the Invisible.