1. \Knowl"edge\, n. [OE. knowlage, knowlege, knowleche,
   knawleche. The last part is the Icel. suffix -leikr, forming
   abstract nouns, orig. the same as Icel. leikr game, play,
   sport, akin to AS. l[=a]c, Goth. laiks dance. See {Know}, and
   cf. {Lake}, v. i., {Lark} a frolic.]
   1. The act or state of knowing; clear perception of fact,
      truth, or duty; certain apprehension; familiar cognizance;
      cognition.
            Knowledge, which is the highest degree of the
            speculative faculties, consists in the perception of
            the truth of affirmative or negative propositions.
                                                  --Locke.
   2. That which is or may be known; the object of an act of
      knowing; a cognition; -- chiefly used in the plural.
            There is a great difference in the delivery of the
            mathematics, which are the most abstracted of
            knowledges.                           --Bacon.
            Knowledges is a term in frequent use by Bacon, and,
            though now obsolete, should be revived, as without
            it we are compelled to borrow ``cognitions'' to
            express its import.                   --Sir W.
                                                  Hamilton.
            To use a word of Bacon's, now unfortunately
            obsolete, we must determine the relative value of
            knowledges.                           --H. Spencer.
   3. That which is gained and preserved by knowing;
      instruction; acquaintance; enlightenment; learning;
      scholarship; erudition.
            Knowledge puffeth up, but charity edifieth. --1 Cor.
                                                  viii. 1.
            Ignorance is the curse of God; - Knowledge, the wing
            wherewith we fly to heaven.           --Shak.
   4. That familiarity which is gained by actual experience;
      practical skill; as, a knowledge of life.
            Shipmen that had knowledge of the sea. --1 Kings ix.
                                                  27.
   5. Scope of information; cognizance; notice; as, it has not
      come to my knowledge.
            Why have I found grace in thine eyes, that thou
            shouldst take knowledge of me?        --Ruth ii. 10.
   6. Sexual intercourse; -- usually preceded by carnal; as,
      carnal knowledge.
   Syn: See {Wisdom}.
   

2. \Knowl"edge\, v. t.
   To acknowledge. [Obs.] ``Sinners which knowledge their
   sins.'' --Tyndale.
   

The objects, concepts and relationships that are assumed to exist in some area of interest. A collection of knowledge, represented using some knowledge representation language is known as a knowledge base and a program for extending and/or querying a knowledge base is a knowledge-based system.

Knowledge differs from data or information in that new knowledge may be created from existing knowledge using logical inference. If information is data plus meaning then knowledge is information plus processing.

A common form of knowledge, e.g. in a Prolog program, is a collection of facts and rules about some subject.

For example, a knowledge base about a family might contain the facts that John is David's son and Tom is John's son and the rule that the son of someone's son is their grandson. From this knowledge it could infer the new fact that Tom is David's grandson.

See also Knowledge Level.