promoter

from The American Heritage® Dictionary of the English Language, 5th Edition.

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

from The Century Dictionary.

• noun One who or that which promotes, forwards, or advances; an encourager: as. a promoter of charity.
• noun One who aids in promoting some financial undertaking; one engaged in getting up a joint-stock company; one who makes it his business to assist in the organization and capitalizing of corporations.
• noun An informer; specifically, a person who prosecuted offenders as an informer in his own name and the king's, receiving in reward part of the fines or penalties.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who, or that which, forwards, advances, or promotes; an encourager.
• noun Specifically, one who sets on foot, and takes the preliminary steps in, a scheme for the organization of a corporation, a joint-stock company, or the like.
• noun One who excites.
• noun obsolete An informer; a makebate.
• noun (Genetics) The region of a DNA molecule to which RNA polymerase binds to initiate the process of transcription, i.e. the synthesis of RNA whose sequence is determined by the sequence of the DNA adjacent to the promoter site; also, the sequence of bases in the DNA at such a promoter site.
• noun (Chem.) A substance that increases the activity of a catalyst, when present in small quantity in the reaction mixture.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One who promotes, particularly with respect to entertainment events or goods.
• noun genetics The section of DNA that controls the initiation of RNA transcription as a product of a gene.
• noun An accelerator of catalysis, though not itself a catalyst.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone who is an active supporter and advocate
• noun a sponsor who books and stages public entertainments