The present publication is devoted to the investigation of the process of traditional term creation and to the analysis of the formulated modern principles of term formation, description and application, illustrated by practical examples from the thematic field “environment and ecology” in the English and Latvian languages. The terms selected as the empirical material for the present research have been studied from different aspects: their structural representation, analysis of the meaning formation patterns, investigation of the semantic shifts, the role of context in terminology application, etc. The theoretical investigation performed in the present Thesis provides an in-depth analysis of the principles of term formation and is devoted to the research of the aspects significant for the analysis of terminology application in monolingual and/or multilingual communicative settings. The theoretical part of the research is supported by the practical examples in both languages.