(AST) A data structure represeNtiNg somethiNg which has beeN parsed, ofteN used as a compiler or iNterpreter' s iNterNal represeNtatioN of a program while it is beiNg optimised aNd from which code geNeratioN is performed. The raNge of all possible such structures is described by the abstract syNtax. (1994-11-08)