University of Victoria (Canada)
The U Vic Writer's Guide: Literary Term: Drama
The University of Victoria's English department gives a comprehensive definition of "drama" in writing.
Other
Bob's Byway: Glossary of Poetic Terms
Calling itself "unique," Bob's is easy to use, with cross-links throughout, phonetic pronunciation guides when necessary, and many examples and quotations. Click on the letter and scroll for the word.