The paper reveals the concept of an "abbreviation-quasi-abbreviation group", which is treated as a set ofnests of equivalence of abbreviations and quasi-abbreviations having an identical abbroconstruct. The relevanceof the study is accounted for by the need to clarify the typology of abbreviation groups, aimed at determining thediachronic and synchronous statuses of the compound words they are constituted by. A number of methods havebeen applied in the course of the study, among them are the methods of observation, and generalization, as well assuch techniques of diachronic analysis of abbreviations as the chronological, quantitative, and semanticinterpretative ones. The source of the empirical material was the database of abbreviation dictionaries and thecorpus of abbreviation texts at the Russian Language Department in Donetsk State University. A comprehensiveanalysis of the abbreviation-quasi-abbreviation group "euro" has been carried out. The abbreviation structuredescription has been given. Varieties of the abbreviations equivalence nests have been identified. The decodingmatrix structure has been determined, as well as the formal-structural and onomasiological features of thecomponents it is constituted by.