X′ theory

A form of X-bar theory — A theory that posits a common syntactic structure for different lexical categories. Each phrase (XP) is the projection of a head (X) and may optionally include a specifier (sister of X-bar, daughter of XP), adjuncts (sister and daughter of X-bar) and complements (sister of X, daughter of X-bar).

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Meanings

nounX′ theory (uncountable)
  1. alternativeuncountableAlternative form of X-bar theory.
Cite this entry
APA

X′ theory. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/X%E2%80%B2%20theory

MLA

“X′ theory.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/X%E2%80%B2%20theory. Accessed November 5, 2026.

Chicago

WatkinsX Dictionary, s.v. “X′ theory,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/X%E2%80%B2%20theory.

Source: X′ theory on Wiktionary, CC BY-SA 4.0.