In ancient Greece, theatrical presentations were strictly defined as being either tragedy or a comedy. In modern entertainment, drama is defined as a genre applicable to any theatrical play, TV series or film dealing with non-comedic subject matter. Modern drama will often contain elements of other genres, and it is not uncommon to see "light" or comedic drama or so-called "black comedies" that make light of dramatic subject matter.
The original definition of tragedy was provided by Aristotle, who defined tragedy as a form of drama in which the protagonist has a tragic flaw, such as excessive pride. This flaw will cause him to take an action that triggers an unfortunate series of events that will ultimately lead to his own downfall. Typically these protagonists were men of power and stature; the greater the distance the protagonist fell, the greater the tragedy.
Modern examples of drama are virtually endless, with new dramatic films released on a weekly basis. On television, dramas typically center on three occupations: doctors, lawyers and police, the so-called "holy trinity" of TV drama.
An example of Greek tragedy is the story of Oedipus, who slept with his mother, killed his father and gouged out his own eyes over the horror of what he had done. One of the most enduring tragedies is William Shakespeare's "Hamlet," whose tragic flaw was his indecision.
One of the differences between drama and tragedy is that a tragedy is necessarily a drama, but a drama need not necessarily be a tragedy. Another key difference is that the protagonist in a drama may not possess a tragic flaw that results in his own downfall.