Religious people often refer to things like a spirit or a soul, but what exactly do they mean when they say this? I've attempted on multiple occasions to extract a coherent definition to no avail.

The last unfortunate individual could only go so far as to compare it with breath.

But we already have a word for breath...it's breath. So it seems to be a superfluous term in this scenario.

Can anyone proctor a meaningful definition of what a spirit is and what reasons we have to suspect that it does exist? After a satisfactory definition of what a spirit is, it seems to me that we ought address what a spirit does. What function does it serve in our lives and how do we know it is responsible for this function?

It's the personal instructions were are programmed with by nurture and nature

The air of heaven would burst your lungs.
The music of heaven would drive you insane.
The light of heaven would blind you.
Only the spirit can bare heaven's touch.

What is the force, from Star Wars, to you when hear it?

A spirit is a ghost. I'm not religious or a spiritual person but yeah to me a 'Spirit' would be a ghost.

Or the thing that defines somethings energy as in "get in the spirit of christmas".

I'm talking about in the context of religion, not the paranormal. The other example is not literal, but poetic.

Well, it's a fictional Universe so I don't see the connection at all to be honest. It's like asking me why Superman can fly. 

In this fictional Universe, there is some natural force called "the force" which binds together everything. 

A strong distilled liquor such as brandy, whiskey, gin, or rum.

A fabrication created out of fear of death.

spirit? spirit of 33?