Promoter: has multiple closely related but subtly different meanings depending on context:

  * In bacteria, a promoter is a cis-acting DNA sequence near the transcription start site of a gene or operon that binds to bacterial RNA polymerase. 
  * In eukaryotes, the formal definition of a promoter (also called a basal promoter) is a cis-acting DNA sequence near the transcription start site of a gene that binds to the basal transcription factors (also called general transcription factors), which collectively form a scaffold upon which eukaryotic RNA polymerase (usually RNA pol II) can bind to form the transcription initiation complex. The TATA box is a component within the promoter of most eukaryotic genes.
  * In a general and less formal sense, "promoter" refers to any DNA sequences near a gene that regulates its expression. In this informal usage, "promoter" can be refer to a region of DNA thousands of bp in size and can include enhancer sequences.