Definition
Prolog
Prolog is a logic programming language in which a program is written as a collection of facts and rules, and computation is performed by trying to prove a query from those rules.
It is based on the proof-search idea behind the propositional resolution calculus: to answer a query, Prolog tries to derive it by resolution-like steps. In full Prolog, this idea is extended from propositional clauses to first-order Horn clauses using unification.