"Categories are likely to be arranged in a hierarchical fashion, particularly if they are associated with words. All lexical items are part of a hierarchical structure (Fig 17.1). When we are asked to say what a word means, we usually answer in terms of such a hierarchy: 'a spaniel is a kind of dog used in hunting'." (Maynard-Smith & Szathmary, 1995, p.285)
Compare this with the Celestial Emporium of Benevolent Recognition.