5GL 【Fifth-generation programming language】
5GL is an abbreviation for fifth-generation language. Fifth-generation programming languages emerged along with the research in Artificial Intelligence (AI). Most constraint-based and logic programming languages and some declarative languages are fifth-generation languages. Fifth-generation languages are designed to make the computer solve the problem for you as oppose to using an algorithm written by a programmer.
The idea of fifth generation languages was popular in 1990s. Japan put much research and money into their fifth-generation computer systems project. Prolog, Mercury, and OPS5 are the best known fifth-generation languages.