The clinical communication space refers to the activities that take place in the context of clinical communication. Communication is an important part of healthcare delivery yet the communication space has been described a source of medical errors and other communication issues such as interruptions. Information and communication technologies (ICTs) can enhance the clinical communication space but before we can design ICTs we need to describe the space. In particular we need to understand the role that informal communication plays. This paper reports on an exploratory study of the clinical communication space. It uses an ontology to illustrate the range of processes, modalities and contexts within the communication space and the role of formal, informal and hybrid communication.