From The Collaborative International Dictionary of English v.0.48 [gcide]:
2. Act of ascertaining and explaining the signification; a description of a thing by its properties; an explanation of the meaning of a word or term; as, the definition of "circle;" the definition of "wit;" an exact definition; a loose definition.
Usage: A definition is designed to settle a thing in its compass and extent; an explanation is intended to remove some obscurity or misunderstanding, and is therefore more extended and minute; a description enters into striking particulars with a view to interest or impress by graphic effect. It is not therefore true, though often said, that description is only an extended definition. "Logicians distinguish definitions into essential and accidental. An essential definition states what are regarded as the constituent parts of the essence of that which is to be defined; and an accidental definition lays down what are regarded as circumstances belonging to it, viz., properties or accidents, such as causes, effects, etc." --Whately.
From WordNet (r) 3.0 (2006) [wn]:
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