What is the difference between drama and tragedy?

Drama- 
A prose or verse composition, especially one telling a serious story, that is intended for representation by actors impersonating the characters and performing the dialogue and action. 
A serious narrative work or program for television, radio, or the cinema. 
Theatrical plays of a particular kind or period: Elizabethan drama. 
The art or practice of writing or producing dramatic works. 
A situation or succession of events in real life having the dramatic progression or emotional effect characteristic of a play: the drama of the prisoner's escape and recapture. 
The quality or condition of being dramatic: a summit meeting full of drama. 
[Late Latin drāma, drāmat-, from Greek, from drān, to do, perform.] 

Full Definition of TRAGEDY

1

a :  a medieval narrative poem or tale typically describing the downfall of a great man

b :  a serious drama typically describing a conflict between the protagonist and a superior force (as destiny) and having a sorrowful or disastrous conclusion that elicits pity or terror

c :  the literary genre of tragic dramas

2

a :  a disastrous event :  calamity

b :  misfortune

3

:  tragic quality or element

Source(s):

http://www.answers.com/topic/drama 

http://www.merriam-webster.com/dictionary/tragedy