Hallelujah..

What exactly does it mean, and what emotions and feelings would one associate with it? Why and when do people sing/say it? Pl tell me all you can about this..

If my memory serves me,it means praise Jah
which is a shortened form of the name of God in the Bible so basically you would say it whenever you want to say praise God.

I just learnt the meaning of this word this weekend, but I forget the exact definition. It's something like "Unrestricted praise to God".
I could be wrong though, but it does have something to do with praise.