Systemic approach to a language for special purposes is a prerequisite for organizing scientific knowledge into the smaller research units, which significantly facilitates analysis of different phenomena. The organization of inner structure of a language for special purposes is related to the development of a related scientific field, thus forming a unified cognitive mechanism for accumulating, storing, processing, and communication of field-specific knowledge in both monolingual and multilingual environments. The cognitive view on terminology requires considering frames and frame sets, which form different terminological systems within a thematic field. Terminological systems incorporated into the thematic field “Environment and Ecology” are dynamic and open to changes. Their elements may appear not only in different fames and their sets within the given system but also beyond it, contributing to the building of thematic, logical, derivative, semantic, and paradigmatic relations among the terms, at the same time establishing relations of emotive nature. These relations appear because of the changes in the application of the terms in texts and due to formation of a new communication practice, which recognises the extended role of the appellative rhetoric strategies for the transfer of field specific knowledge. Within the framework of the present paper the author has analysed the use of pathos as meaning component for formation of variants of the Latvian terms “videi draudzīgs” and “videi nedraudzīgs”. The necessity to modify the existing terms and/or create the new ones is always a strategic decision. The newly created lexical units differ in status, frequency of use, context of application, and appellative load they may carry.