Biomedical Informatics: The science of managing information for health care, research, education, and administration by applying, integrating, and evaluating information technology along with its associated policies, procedures, and organizational cultures. This includes the study of all forms of information technology from paper through to high performance computers.
An interdisciplinary science, Biomedical Informatics extends across the domains of other sciences, creating sub-specialty fields within the field of biomedical informatics as shown below:
The field of biomedical informatics is still a young one. Therefore you may find many different definitions. The American Medical Informatics Association has a list of definitions compiled from various sources.