Frisse et al. defined medical informatics as being at the crossroads between biomedical science and information technology, with a focus on developing and delivering information systems that support health care, decision making, databases for outcomes analysis, and health sciences research and administration. Health sciences librarianship was viewed as theorizing about and applying organizational and management technologies to biomedical scholarly communications. The authors noted that their definition of informatics focused on tasks for the field and did not encompass informatics' intellectual scope, so that their description of librarianship was in fact relevant to both librarianship and informatics as the disciplines then existed.
Given the continued evolution of both informatics and librarianship, it is worthwhile to review some additional definitional aspects and to further consider the relationships between informatics, health sciences librarianship, and the broader domain of information science. Varied terminology is used in the informatics field. One approach differentiates areas of informatics by the practice area covered, as in clinical informatics, nursing informatics, public health informatics, and so on. Some practitioners use the term bioinformatics to reflect informatics activity related to the basic sciences, most especially those dealing with genetics. Others use the term bioinformatics to describe the range of subdisciplines in the broad area of informatics applications in the health sciences. The American Medical Informatics Association encompasses the subdisciplines under the general term “medical informatics,” although changing the association's name has been regularly discussed.
Four definitions of informatics, created over a span of more than twenty-five years, illustrate key elements in the evolution of the field:
- 1977: Medical informatics is the application of computer technology to all fields of medicine—medical care, medical teaching, and medical research. 
- 1984: Medical informatics comprises the theoretical and practical aspects of information processing and communication, based on knowledge and experience derived from processes in medical and health care. 
- 1990: We define medical informatics as the rapidly developing scientific field that deals with the storage, retrieval, and optimal use of biomedical information, data, and knowledge for problem solving and decision making. 
- 2003: Biomedical informatics is the interdisciplinary science that deals with biomedical information, its structure, acquisition, and use. “Biomedical” is used here in its broadest sense, to include research, education, and service in health-related basic sciences, clinical disciplines, and health care administration. Biomedical informatics is grounded in the principles of computer science, information science, cognitive science, social science, and engineering, as well as the clinical and basic sciences. Biomedical informatics encompasses a spectrum similar in scope to the sequence from mathematics to physics to engineering. It includes scientific endeavors ranging from theoretical model construction to the building and evaluation of applied systems. 
Another recent definition of informatics, put forth by Stead as a simplification but nonetheless capturing the essence of the field, is, “medical informatics is the science that deals with health information, its structure, acquisition and use” [7
Since Frisse et al. wrote their article, the discipline of health sciences informatics has significantly broadened, with the beginnings of greater integration of concepts in the field's component parts. In 1995, recognized areas of informatics concerned clinical medicine, nursing, and dentistry. Over time, every discipline under the umbrella of health sciences has recognized the extension of concepts related to advanced computing technologies to the delivery of patient care.
In recent years, informatics concepts have additionally been useful in dealing with other health-related kinds of data, especially basic science and public health information. While built on similar principles of information management, each discipline has unique needs with diverse types of data and unique and often disparate operations performed on that information. New subfields of informatics continue to be identified, and a number of professional medical societies now recognize informatics activities related to the particular data, information, and knowledge in their domain. Examples include primary care and oncology informatics [8
]. How then do evolving definitions of informatics and the expanding nature of its professional domain affect and relate to the already established domains of library and information science?