1. Computer Definition [Design?] Language. A hardware description language. "Computer Organisation and Microprogramming", Yaohan Chu, P-H 1970.2. Command Definition Language. Portion of ICES used to implement commands. Sammet 1969, p.618-620. 3. Compiler Description Language. C.H.A. Koster, 1969. Intended for implementation of the rules of an affix grammar by recursive procedures. A procedure may be a set of tree-structured alternatives, each alternative is executed until one successfully exits. Used in a portable COBOL-74 compiler from MPB, mprolog system from SzKI, and the Mephisto chess computer. "CDL: A Compiler Implementation Language", in Methods of Algorithmic Language Implementation, C.H.A. Koster, LNCS 47, Springer 1977, pp.341-351. "Using the CDL Compiler Compiler", C.H.A. Koster, 1974. Versions: CDL2, CDLM used at Manchester. 4. Common Design Language. "Common Design Language", IBM, Software Engineering Inst, Sept 1983. 5. Control Definition Language. Ideas which contributed to Smalltalk. ["Control Structures for Programming Languges", David A. Fisher, PhD Thesis, CMU 1970].