The words data and information are used without sufficient delineation of HOW, WHERE and WHEN to use them. They are at times used interchangeably and the dictionary meanings which seek to distinguish data and information end up with cyclic references. The use of these terms in computer science and information technology also follow the same colloquial trend with some pseudo-scientific attributions (raw facts are data and processed data is information) that do not pass simple tests of validity or rigor.
At times the word knowledge is used to explain the meanings of data and information, compounding the confusion and not having its own meaning. Donald E Knuth’s definitions of data and information are sufficiently precise and rigorous to be called scientific. Unfortunately Knuth's definitions of "data & information" do NOT turn up in the search results of Google, Yahoo, Bing, WolframAlpha. It seems perhaps the SINGLE AUTHENTIC source is vanishing. One definition of "data" which comes very close is from Dictionary of Military and Associated Terms.
They are discussed and used as foundation to define knowledge.
Knuth’s definition of “information” includes the word “meaning” which itself is a very complex and is wrongly defined in most places (according to me). I have a proposed definition for meaning also…too long). It is NOT essential to bring in the concept of "meaning" in the definition of "information". This is a new addition (09OCT13).
The available definitions of knowledge are examined and contrasted with Knuth’s definition of Data and Information. It is argued that “knowledge” refers to the “ability of a person or entity” “to provide data or information” “in response to a query”. This provides basis for knowledge representation, authoring and processing (separately described).