Absys was an early declarative programming language from the University of Aberdeen. It anticipated a number of features of Prolog such as negation as failure, aggregation operators, the central role of backtracking and constraint solving. Absys was the first implementation of a logic programming language.
The name Absys was chosen as an abbreviation for Aberdeen System.
See also ABSET
References
"ABSYS: An Incremental Compiler for Assertions", J.M. Foster et al., Mach Intell 4, Edinburgh U Press, 1969, pp. 423–429