Prolog is a logic programming language that is based on formal logic and mathematical reasoning. The name "Prolog" stands for "Programming in Logic."

It was developed in the 1970s by Alain Colmerauer and Philippe Roussel at the University of Aix-Marseille in France.

Prolog is different from traditional imperative or object-oriented programming languages. Instead of specifying how to solve a problem step by step, Prolog focuses on describing the problem in terms of logical relationships and rules. It allows programmers to define facts, rules, and queries, and then the Prolog interpreter or compiler can automatically search for solutions by applying logical inference and backtracking.

In Prolog, programs are composed of a collection of facts and rules. Facts represent knowledge about the world, while rules define relationships and logical constraints. Prolog uses a process called unification to match queries against the available facts and rules and find solutions. If a solution is found, Prolog can backtrack and explore alternative solutions.

Prolog has been widely used in areas such as artificial intelligence, natural language processing, expert systems, theorem proving, and symbolic computation. It has a declarative and concise syntax, which makes it suitable for expressing complex problems and exploring different search strategies. Prolog programs can be executed interactively or compiled into standalone executables.