While they offer convenient formalisms and better packaging mechanisms, even object-oriented models have a distinctive conceptual and expressive bias. For conceptual models, "thinking outside the box" takes on a whole new meaning. In fact, our thinking does exceed the rectangular borders of our object models. We must remember that there are concepts other than simple nouns (objects) and verbs (methods). Our language offers a rich panoply of descriptive qualities and case relations, if only we can find meaningful use for them in our models. The following table provides a brief summary of this richness.

Class Subclass Indication
adjective descriptive adjective quality, instantiation, differentiation (classification)
  limiting adjective quantity, limit, index, factor
  graduated adjective positive, comparative, superlative
verb transitive verb action, relationship
  intransitive verb action
noun common noun person (role), place (space/time), object (class)
  proper noun identification (name)
  pronoun reference, possession
preposition predicative preposition participation
  possessive preposition possession
conjunction coordinate conjunction inclusion, exclusion, conclusion, contrast
  subordinate conjunction reason, degree, concession, condition, manner, place, purpose, time
  correlative conjunction inclusion (both-and), exclusion (either-or, neither-nor), conclusion (if-then)
adverb descriptive adverb affirmation, negation, doubt, reason, degree, manner, number, time, place, location, direction
  interrogative adverb choice (whether), reason (why), manner (how), time (when), place (where), origin (whence), direction (whither)
  demonstrative adverb choice (thus, then, hence), time (now, then, hence), place (here, there), direction (hither, thither, hence, thence)
  conjunctive adverb inclusion