Trance, as a class term, is a categoric auspice or rubric, employed to denote a variety of processes, techniques, modalities and states of mind, awareness and consciousness.Trance states may be consciously and intentionally induced, or they may occur involuntarily and unbidden.The term "trance" may be conflated with others such as meditation, play, magic, flow and prayer. It may also be conflated with the earlier generic term, altered states of consciousness, which, due to the value judgement that is embedded within the adjective "altered", is no longer used in "Consciousness Studies" discourse.
Trance: etymology
Trance is from Latin 'trans?re': to cross, pass over and the multiple meaning of the polyvalent homonym "entrance" as a verb and noun provide insight into the nature of trance as a threshold, conduit, portal and/or channel.Trance, n. [F. 'transe' fright, in OF. also, trance or swoon, fr. 'transir' to chill, benumb, to be chilled, to shiver, OF. also, to die, L. 'transire'
Source:
http://en.wikipedia.org/wiki/Trance