Abstract Since the leading form of scientific thinking is the concept, almost every word in a scientific text is expressed by special lexical units - terms. The term is a denoting word or phrase characteristic of this branch of science and technology, and it has strict semantic boundaries. Accordingly, terminology is a system of concepts of the given science, fixed in the corresponding verbal expression. If in a common language (outside of this terminology) a word can be polysemantic, then, coming into a certain terminology, it becomes monosemantic, and the translation uses a meaning different from that used in everyday life. A clear definition allows us to separate one phenomenon from another, to identify significant differences between them and thus emphasize a deeper understanding of the phenomena themselves. Therefore, the purpose of this work is an attempt to understand the meaning of today’s fashion terms with the terminological element “nano” – “nanoscience”, “nanotechnology”, “nanomaterial”. Despite the fact that these issues have been repeatedly discussed in the special and popular science literature, the analysis of such literature shows that even in wide scientific circles, not to mention unscientific, there is no clear understanding of both the problem and the definitions. That is why we will try to show the meaning of the term “nano”, with the help of which they designate a new era in the development of technologies, sometimes called the fourth industrial revolution, – the era of nanotechnology. Summing up, we may conclude that for a successful understanding of scientific literature, reader needs to have a certain lexical reserve, including special terms, to know the lexical, grammatical and stylistic rules, properties of creating terms and to be able to use them, and to be guided in the specific field of scientific knowledge.