1. One that promotes, especially an active supporter or advocate.
2. A financial and publicity organizer, as of a boxing match or an artistic performance.
3. Genetics. The region of an operon that acts as the initial binding site for RNA polymerase.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.