Bioinformatics :Research, development, or application of computational tools and approaches for expanding the use of biological, medical, behavioral or health data, including those to acquire, store, organize, archive, analyze, or visualize such data.
From: The NIH Biomedical Information Science and Technology
Initiative Consortium
Medical Informatics :Medical informatics has to do with all aspects of understanding and promoting the effective organization, analysis, management, and use of information in health care.
From: The American Medical Informatics Association