What's the difference between Computer Science and Informatics?
I deliberately use very common, not necessarily professional resource.

Computer Science


  Computer science is the study of the theory, experimentation, and engineering that form the basis for the design and use of computers. It is the scientific and practical approach to computation and its applications and the systematic study of the feasibility, structure, expression, and mechanization of the methodical procedures (or algorithms) that underlie the acquisition, representation, processing, storage, communication of, and access to information. An alternate, more succinct definition of computer science is the study of automating algorithmic processes that scale. A computer scientist specializes in the theory of computation and the design of computational systems.


source: Computer Science @ Wikipedia

Informatics


  Informatics is a branch of information engineering. It involves the practice of information processing and the engineering of information systems, and as an academic field it is an applied form of information science. The field considers the interaction between humans and information alongside the construction of interfaces, organisations, technologies and systems. As such, the field of informatics has great breadth and encompasses many subspecialties, including disciplines of computer science, information systems, information technology and statistics. Since the advent of computers, individuals and organizations increasingly process information digitally. This has led to the study of informatics with computational, mathematical, biological, cognitive and social aspects, including study of the social impact of information technologies.


source: Informatics @ Wikipedia

It is for sure time and place dependent, after further research it seems that the German term Informatik was a synonym of the Computer Science at first, was adapted virtually everywhere, but evolved since 1956, and diverged with meaning, but it is still overlapping. Tt seems that currently Informatics is used more as applied Computer Science (ref: search engine coin toss).

The IT (Information Technology) in some languages has broader meaning, and simply merges telecommunication with computer sciene and informatics. Unfortunately this is not well-defined term, it is part of the language so it may vary in time up to the moment when people think it is too broad and start some finer classification.

Please see also Informatics vs. Computer Science