Definition of "sortal"

sortal

adjective
not comparable
1. (philosophy) Of or pertaining to a sort, or kind.
  Quotations
  But, it being evident that things are ranked under names into sorts or species, only as they agree to certain abstract ideas, to which we have annexed those names, the essence of each genus, or sort, comes to be nothing but that abstract idea which the general, or sortal (if I may have leave so to call it from sort, as I do general from genus), name stands for.
  1690, John Locke, “Chapter III: Of General Terms”, in An Essay Concerning Human Understanding, Book III
2. (philosophy) Having the character of a sortal.
  Quotations
  The possession of sortal concepts is a prerequisite for philosophers like Wiggins or Lowe in determining the nature and extent of our referential capacities.
  2008 January 8, John E. Sarnecki, “Sortals for Dummies”, in Erkenntnis, volume 69, number 2
noun
plural sortals
1. (philosophy) A type of universal that defines a particular sort of object
  Quotations
  And central to this notion is the distinction, among semantic types of g-words, between sortals on the one hand and non-sortal general-character-specifiers on the other
  1974, P.F. Strawson, Subject and Predicate in Logic and Grammar, page 135