There is a wealth of information about energy, but it is spread across many books, journals, websites, disciplines, ideologies, and user communities. Information about energy tends to target either a particular form of energy or a specific audience. There is no central repository of information that meets diverse user communities, and no primary machinery of communication among those communities. These characteristics of energy information define the formidable barrier to successful teaching and learning related to energy, a barrier we seek to significantly erode, if not eliminate, with the Dictionary of Energy.