decision problem(redirected from Undecidable language)
A problem with a yes/no answer. Determining whether some potential solution to a question is actually a solution or not. E.g. "Is 43669" a prime number?". This is in contrast to a "search problem" which must find a solution from scratch, e.g. "What is the millionth prime number?".
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)