The objective of this study is to identify the Korean copula ‘ida’ as an adjective and discuss grammatical issues regarding ‘ida’ by taking into account not only its multi-dimensional nature but also the whole Korean grammatical system. Until now, there have been many studies focusing on categorization issues, phonological dropping, conjugational characteristics of ‘ida’ and classification of ‘ida’ constructions. While the previous studies have examined individual topics on this copula, few studies have presented a balanced description of ‘ida’ within the whole system of the Korean grammar. Not only do we need to establish the category of ‘ida’ but also it is necessary to discuss the Korean POS and sentence complement systems in relation to the category of ‘ida’. This study is organized as follows. Chapter 2 describes the characteristics of ‘ida’ from the perspective of copula typology and provides an analysis of the most frequent patterns of ‘ida’, based on the lists of POS taggers and types in [n±1] of ‘ida’ in morphologically tagged Korean corpus. Furthermore, we show the conjugational similarities between ‘ida’ and ‘anida’. Chapter 3 contends that ‘ida’ finds a more appropriate place in the Korean POS and sentence complement systems if identified as an adjective. That is to say, the Korean copula ‘ida’ being described as an adjective provides answers to issues related to the Korean morpho-syntactical system.