Drama is a term that covers all literature written to be performed on stage. It is a broad term like poetry, novel, or fiction. There are many subcategories of Drama, and Tragedy is one of them. Tragedy is to drama like sonnet is to poetry.
All works of drama rely on characterization, stage directions, aside, and setting to tell their stories. Tragedies have these characteristics as well. Tragedies, however, include a few other important elements that are unique to only tragedies and no other form or drama. These elements are:
A tragic hero: In a tragedy, the protagonist is a tragic hero who will suffer a downfall due to his or her tragic flaw.
A tragic flaw: A tragic hero's tragic flaw is a character trait that he or she encompasses that causes his or her weakness and ultimately his or her downfall.
A Downfall: A downfall is a tragic end. In Shakespeare, it is often death, but it may also include removal from a position of power or respect.
For example: Shakespeare's Romeo and Juliet is a Tragedy. Romeo and Juliet are both tragic heroes in the play. Their tragic flaw is haste. Both act without fully thinking through their actions and the consequences of their actions, thus acting in haste. This hastiness causes their downfalls which in this play is untimely dead by suicide.