A chordal graph is a type of graph in which every cycle of four or more vertices has a chord. A chord is an edge that connects two non-adjacent vertices in the cycle. This property ensures that the graph does not contain any "long" cycles, making it easier to analyze and work with in various applications. Chordal graphs are significant in areas such as computer science, graph theory, and optimization. They are often used in algorithms for tasks like graph coloring and clique finding, where their structural properties can lead to more efficient solutions.