The aim of this article is to increase understanding of tacit knowledge as a phenomenon and also, to specify and understand tacit knowledge of an expert in a given context. In the discourse of organizational behavior, the use of the concept of tacit knowledge and empirical scientific research on it has become more popular only in the 1990s. The strong increase in expert work and knowledge‑intensive fields make examining the topic timely and both theoretically and practically interesting. The most significant theoretical contribution of the study is the increase in understanding, as well as, the creation of new knowledge of the contents and the nature of tacit knowledge. Based on our study, it seems that the current division of knowledge to explicit and tacit is not sufficient to describe the phenomenon. It has been proposed that explicit knowledge is visible and “articulated” knowledge that can easily be transferred and codified, e.g., through speech, documents and various information management systems. Implicit knowledge, on the other hand, is “silent”, hidden and non‑verbal knowledge that is difficult or even impossible to transfer and express verbally. We propose that tacit knowledge comprises different components, some of which can be articulated and made explicit. Examples of such are individual’s or organizations accustomed lines of action that are based on explicit instructions. On the other hand, individual‑specific tacit knowledge that includes feelings, emotions and intuition, individual’s intuitive behaviour or personal relationships, can be considered as “the genuine tacit knowledge” in the sense that it cannot be made visible or transferred. These findings suggest that the interconnectedness of explicit and tacit knowledge ought to be examined further.