X-bar schema

Definition
X-bar schema is a generalization based on X-bar theory, summarizing the assumption that all major syntactic categories N, V, A, P, as well as functional categories such as I(NFL) and C(OMP) essentially project the same structure:

(i) a [X' X Y"]     b  [X" Z" X']

where Y" in (i)a is the complement of the head X, and Z" in (i)b is the specifier of X. X" is equal to XP and is called the maximal projection of X.

Links

 * Utrecht Lexicon of Linguistics