A simplicial complex is a mathematical structure used in topology, which is a branch of mathematics that studies the properties of space. It is formed by combining simple shapes called simplices, such as points (0-simplices), line segments (1-simplices), triangles (2-simplices), and higher-dimensional analogs. These simplices are connected in a way that satisfies certain conditions, allowing for the study of their geometric and topological properties. Simplicial complexes can represent various types of data and spaces, making them useful in fields like computer science, data analysis, and algebraic topology. They help in understanding the shape and connectivity of data, enabling researchers to analyze complex structures in a simplified manner.