• (1) A definition is an answer to such questions as:
  ‘what is the nature of x?’ ‘What is virtue?’
  
  
• (2) A definition focuses upon a common nature, an eidos (72a-c)
  
  
• (3) A definition states what is the same in a number of things, i.e. the definiendum. (72d)
  
  
• (4) A definition seeks to define a thing by means of a unique definite description, or to understand the structure of an eidos that is common to several things. (cf. 75b and 76a)
  
  
• (5) Definition seeks the single thing that runs through and is common to many particulars (74a-b).
  
  
• (6) It is possible to define with respect to one thing (the idea) what it is to be one of a set of things.
  
  
• (7) A common name among many things is possible only because they have a common nature, and the name refers to that common nature.
  
  
• (8) Definition looks for that which is the same element common to all these things that bear a common name. (75a)
  
  

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[George Nakhnikian, "Elenctic Definitions," in G. Vlastos [ed.], The Philosophy of Socrates (Doubleday 1971), 125-157, at 126-6 and 132.]

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