The way metalanguage is used in research directly influences the accurate representation of scientific thought in the description, theorisation and analysis of the phenomena under study. Therefore, language as a means through which scientific concepts are illuminated is worth some serious attention. This article examines the use of key terminology in research publications in the field of syntax which deal with the linguistic status, the specific features, and the typology and realisations of the appositive construction. The main focus of analysis is on the inconsistent use of terms such as apposition, appositive, appositivity, appositional, and their derivatives and word combinations of a terminological nature. The arbitrary mixing and replacement of these key terms often result in significant problems regarding the meanings conveyed in the texts in which they are used and their interpretation. The study also provides a systematic review of fundamental terms and discusses some debatable solutions to their use in linguistic studies in Bulgarian, English, German, and Russian.