What's The Difference Between Drama And Theatre?

Drama and Theatre are words that are used interchangeably, but do not necessarily mean the same thing.  Drama's meaning comes from the Greek and means 'to do' and 'action', which is the heart of dramatic activity. Theatre is the name of a building in which drama takes place, it can also refer to the professional practice of making drama in the building of the same name.

Within an educational institution, theatre studies is the academic study of the subject, whereas drama is the practical aspect.  This is closer to the Greek meaning and close to heart of 'action'

Drama is also the name for the branch of literature that is concerned with playscripts, rather than poetry and prose.
It can also refer to the writing and production of plays.  These meanings seem to contradict the meanings that I originally wrote above, but it is often because of the interchange between the words in which the semantics have become blurred.