A push-down stack, also known as a LIFO (Last In First Out) stack, is a data structure used in computer science to store and retrieve data elements. Some synonyms for the term push-down stack include stack, stack memory, last in first out buffer, and LIFO stack. Additionally, other related terms include stack pointer, which is a memory address pointing to the top of the stack, and pop, which refers to removing an element from the top of the stack. Push-down stacks are commonly used in software development and programming languages to manage function calls, expression evaluation, and program flow control.