Full Idea
If one considers Aristotle's standard example of a definition, then it is plausible that its defining terms ('plane figure' in the case of a circle) should be constitutive of it in the same general way as physical matter constitutes something physical.
Gist of Idea
The components of abstract definitions could play the same role as matter for physical objects
Source
Kit Fine (Aristotle on Matter [1992], 1)
Book Reference
-: 'Mind' [-], p.37
A Reaction
It strikes me that an appropriate translation for the Greek 'hule' might be the English 'ingredients', since Fine seems to be right about the broad application of hule in Aristotle.