Dynamic arrays are a type of data structure that can change in size during program execution. Unlike static arrays, which have a fixed size, dynamic arrays can grow or shrink as needed, allowing for more flexible memory management. This adaptability is particularly useful when the number of elements is unknown at compile time. In many programming languages, such as Python and Java, dynamic arrays are implemented using built-in data types like lists or ArrayLists. These structures automatically handle memory allocation and resizing, making it easier for developers to manage collections of data without worrying about the underlying complexities.