Subcategorization

Definition
Subcategorization is a concept by which differences in syntactic valency between words is expressed. Subcategorization of heads (in particular V) in terms of the phrasal categories (NP, PP, etc.) which they select as a complement. Sometimes strict subcategorization is equated with c-selection.

Example
A transitive verb has to be followed by a direct object NP contrary to intransitive verbs. We can say that transitive verbs form a subcategory of the category of verbs, by virtue of the fact that they must be followed by an NP complement. It is the obligatory presence of the object which gives rise to the subcategory of transitive verbs. The object subcategorizes the verb, or the verb is subcategorized by the object.

Links

 * Utrecht Lexicon of Linguistics