A LIFO Stack (Last In, First Out) is a data structure where the last item added is the first one to be removed. This behavior is similar to a stack of plates; you add new plates on top and take the top plate off first. It is commonly used in programming for managing function calls, undo mechanisms in applications, and parsing expressions. In a LIFO stack, operations typically include push (to add an item) and pop (to remove the top item). This structure is essential in various algorithms and is often implemented using arrays or linked lists. Understanding LIFO stacks is crucial for grasping concepts in computer science and software development.