Syntactic ambiguity

Syntactic ambiguity, also known as structural ambiguity, amphiboly, or amphibology, is characterized by the potential for a sentence to yield multiple interpretations due to its ambiguous syntax. This form of ambiguity is not derived from the varied meanings of individual words but rather from the relationships among words and clauses within a sentence, concealing interpretations beneath the word order. Consequently, a sentence presents as syntactically ambiguous when it permits reasonable derivation of several possible grammatical structures by an observer.

In jurisprudence, the interpretation of syntactically ambiguous phrases in statutory texts or contracts may be done by courts. Occasionally, claims based on highly improbable interpretations of such ambiguities are dismissed as being frivolous litigation and without merit. The term parse forest refers to the collection of all possible syntactic structures, known as parse trees, that can represent the ambiguous sentence's meanings. The task of clarifying which meaning is actually intended from among the possibilities is known as syntactic disambiguation.

Different forms

Globally ambiguous

A globally ambiguous sentence is one that has at least two distinct interpretations and where reading the entire sentence does not resolve the ambiguity. Globally ambiguous sentences exist where no feature of the representation (e.g., word order and/or grammatical inflection) distinguishes the possible distinct interpretations. Global ambiguities are often unnoticed because readers tend to choose the interpretation they understand to be more probable.