Discrete Structures refers to the study mathematical structures that are individually separate and distinct rather than continuous. As opposed to the study of calculus or real numbers which deal with continuous variables, Discrete Structures deals with graphs and statements in logic which can be enumerated through the implementation of integers.
Since the study of integers percolate through almost every discipline of Mathematics, Discrete Structures can be more appropriately defined by what it excludes: continuous variables. Thus, in this light, a variety of mathematical topics can be categorized under Discrete Structures, which range from Set Theory to Algebraic Structures such as Rings and Fields to Graph Theory.
Although the main definition and objective is to study discrete objects, modern analytical methods have used Discrete Math to study continuous variables. Thus, understanding Discrete Structures is crucial for not only the study of Discrete Math, but also Mathematics in general, due to both the extensive and expansive dispersion of these objects in other mathematical disciplines.