What is medical informatics?

Simplistic definition: Computer applications in medical care
Better definition:
   Biomedical Informatics is an emerging discipline that has been defined
   as the study, invention, and implementation of structures and
   algorithms to improve communication, understanding and management of
   medical information.  The end objective of biomedical informatics is
   the coalescing of data, knowledge, and the tools necessary to apply
   that data and knowledge in the decision-making process, at the time
   and place that a decision needs to be made.  The focus on the
   structures and algorithms necessary to manipulate the information
   separates Biomedical Informatics from other medical disciplines where
   information content is the focus.