The CycL language is a declarative language intended to represent knowledge similar to predicate calculus. Strictly speaking, it is more of a logic language than a programming language.

CycL is used for high level descriptions of common sense concepts suitable for a computer reasoning system. The same language has also been called MELD.

CycL is the language used by the Cyc system or its variants such as OpenCyc.

CycL was developed for the Cyc Project of the MCC, and is now developed by Cycorp in Austin, Texas.