This term seems to be used to refer to a wide array of objects, substances, experiences, places, ect. Personally I feel that it is over used and not to any particular end. Not to mention that it is attached to many things that aren't in the least psychedelic as far as I am concerned.
So, lets hear it. What does psychedelic mean to you? Please, no dictionary or encyclopedia entries.

loosely... something that stimulates one's senses to such a degree that out of the ordinary perceptions are experienced and most often bringing about altered levels of consciousness.

hrm....i would say....something that stimulates your mind in such a way that you cant really distinguish it from reality. i'm not good with the words. bleh.

I perceive it in a induced change of perception, whether by foreign substances or not, stimulated in ways ranging from thought patterns to observable events.

Psychedelic is mostly used synonymously with hallucinogenic, so on the surface, that's what it means to me. However, in a deeper sense, I see psychedelic as referring to something that can stimulate new understanding and insight by altering one's perception (interpretation of the senses) and by offering different perspectives (points of view through which various meanings can be obtained). I really had to think about this one for quite a while before settling for that one statement...but my basic point is that a psychedelic works by altering both immediate experience and how we relate things to one another.

your sig...

These concepts are all valid, but I'm looking for something a bit more broad. I was thinking about this earlier today and there are some situational circumstances that involve no drugs that might be considered as psychedelic in nature. For example; being in a car accident on an interstate or freeway, having a 110 degree fever, enduring a siberian winter without a heat source, complicated surgery w/o anestetics, you get the picture.
Anyone who has ever dropped acid, eaten shrooms, ect. knows exactly what psychedelic is, but how does one put this into words that mean something to the person who has never taken a psychedelic drug? The only reasonable thing I have ever come up with is to ask them if they have ever had a life threatening fever and use that experience to extrapolate some of the details such as your' body melting away, and the mild hallucinations but this usually results in the individual questioning why anyone would ever want to experience that. And this is a pretty poor comparison anyway since it is something that is only borderline psychedelic. What exactly is it about an experience or situation that makes it psychedelic? Or even take a peice of psychedelic art work for example... What quality of the peice makes it such.

I like this response alot, but the only problem I see with it is that it is so broad that all the requirements could be meet by something as simple as reading a good social commentary novel.

unreality.

To me it generally applies to a thought, object, substance, or situation wich has provoked my brain to stretch the fabric of its general processes. The concept of infinity is very psychedelic indeed.

Which is dream and which is reality??

and who is to judge the absolute reality aside from their own perception??

Just to clarify, altering one's perception was meant to include enhancing one's sensory processing in a more direct sense, for example, being able to notice details that are normally out of the range of perception.

psychadelics is the perfect example of us living in a mystical world. you know we are truly unique creatures when you can hallucinate off of a drop of something or a mushroom that grows freely.

I dont even want to think about the shit that would come out of your mouth on a trip.

sometimes I refer to vague/impressionist music and art as psychedelic, descriptively-speaking , because it leaves room for interpretation...and I think interpretation plays a big role in what a person considers psychedelic.

perhaps it's a way of looking at something in a different light (perspective).

I tend to think altered sensory perception is actually a side-effect of a psychedelic experience....the more important component is a higher order of reasoning/intuition/psychic processing, an element not usually present in a cannabis high.

Hmm, to me one of the great defining characteristics of psychedelic experience is that it forces the brain to experience itself with no information filters in place...

Simple, Direct, and to the point. The only thing I'd change is to specify that less filtration takes place instead of no filtration. No filtration would imply a complete dive into the other side such as a massive dose of short acting tryptamines, while other situations can provide psychedelic insight as well.

Other side? What other side? Elaborate please.

I can't help but think about the statement "break on through to the other side" and then of course The Doors and then The Doors of Perception by Aldous Huxley.

But yeah, I'd definitely agree that less filtering takes place, for lack of a better word. Emotional barriers can be breached; conditioning can be bypassed; biases and assumptions can be overrided; and clarity and focus of thought in general can be enhanced (less static, I suppose you could say).

hmm... the other side...
Probably the most rational thing about this concept would be to think of it as a particular degree of psychedelic experience. Some use the term to identify the afterworld which I personally don't believe is significantly different. To dive fully into the other side would mean to loose any connection to your' body or to the rest of the "real" world. Sort of like Alice falling into the rabbit hole but on a much more abstract level. When you are fully given to the other side, you're knowledge and understanding is infinite.

ahh yes...the other side.

breakthrough....hyperspace.

The proverbial DMT flash is the epitome of the other side; complete dissolution.

That's basically what I thought you meant by the other side. That kind of concept is bogus to me because you can't completely lose connection to your body if all you have is your body. And as for knowledge and understanding being infinite, that's a human impossibility.

haha... let the debate begin
If the body is nothing more than a vessel to impose a soul upon the physical realm, then it is very possible to exist without said connection. If you don't believe anything exists outside the physical realm, then according to that system leaving the body would be impossible.
I agree that infinite knowledge and understanding is humanly impossible, but the moment one leaves the "monkey body" and isn't limited by a finite mind, many possibilities that were previously unfathomable become easily attainable.

well, just like you said, no soul, then no leaving the body, so we just have a basic difference in beliefs on that one...and trying to convince me that anyone can have infinite knowledge is like trying to convince me that a speck of sand can know the entire beach