Syntactic ambiguity is a property of sentences which may be reasonably interpreted in more than one way, or reasonably interpreted to mean more than one thing. Ambiguity may or may not involve one word having two parts of speech or homonyms.
Syntactic ambiguity arises not from the range of meanings of single words, but from the relationship between the words and clauses of a sentence, and the sentence structure implied thereby. When a reader can reasonably interpret the same sentence as having more than one possible structure, the text is equivocal and meets the definition of syntactic ambiguity.
In legal disputes, courts may be asked to interpret the meaning of syntactic ambiguities in statutes or contracts. In some instances, arguments asserting highly unlikely interpretations have been deemed frivolous.
Syntactic and semantic ambiguity 
In syntactic ambiguity, the same sequence of words is interpreted as having different syntactic structures. In contrast, in semantic ambiguity, the structure remains the same, but the individual words are interpreted differently.
In headlines 
Newspaper headlines are written in a telegraphic style (headlinese) which often omits the copula and therefore lends itself to syntactic ambiguity, usually of the garden path type. The name 'crash blossoms' was proposed for these ambiguous headlines by Danny Bloom in the Testy Copy Editors discussion group in August 2009 based on a headline "Violinist linked to JAL crash blossoms" that Mike O'Connell had posted, asking what such a headline could be called. The Columbia Journalism Review regularly reprints such headlines in its "The Lower case" column, and has collected them in the anthologies Squad helps dog bite victim and Red Tape Holds Up New Bridge.
Many purported crash blossoms are actually apocryphal or recycled. One celebrated one from World War I is "French push bottles up German rear"; life imitated art in the Second World War headline "Eighth Army Push Bottles Up Germans".
- The cow was found by a stream by a farmer. (Did the farmer find the cow near the stream? Or was the cow found near a stream that was near a farmer? Or did the stream find the cow near a farmer?)
- John saw the man on the mountain with a telescope. (Who has the telescope? John, the man on the mountain, or the mountain?)
- Flying planes can be dangerous. (Either the act of flying planes is dangerous, or planes that are flying are dangerous.)
- They are hunting dogs. (Either "they" are hunting for dogs, or those dogs are a type known as "hunting dogs".)
- Eye Drops Off Shelf. (Describing eye drops that came from a shelf, an eye that fell from its location on a shelf, or an eye that delivered a shelf)
- I'm going to sleep. ("Going" can be a verb with destination "sleep" or an auxiliary indicating near future. So it can mean "I am (now) falling asleep", "I am (in the future) intending to sleep" or "I am leaving (this event) to (go and) sleep")
- The word of the Lord came to Zechariah, son of Berekiah, son of Iddo, the prophet. (Which of the three is the prophet?)
- The British left waffles on Falklands (Did the British leave waffles behind, or is there waffling by the British Left?)
- Monty flies back to front. (Monty returns to the front line, Monty flies backwards, the Monty variety of flies are backwards, or the Monty variety of flies return to the front?)
- The Electric Light Orchestra (An orchestra of electric lights, or a light orchestra that's electric)
- Stolen painting found by tree. (Either a tree found a stolen painting, or a stolen painting was found sitting next to a tree.)
- I'm glad I'm a man, and so is Lola. (can mean "Lola and I are both glad I'm a man", or "I'm glad Lola and I are both men", or "I'm glad I'm a man, and Lola is also a man", or "I'm glad I'm a man, and Lola is also glad to be a man"). Ray Davies deliberately wrote this ambiguity into the song, referring to a cross-dresser.
- Rubber baby buggy bumpers. (Bumpers made of rubber designed for baby buggies, bumpers made for buggies that carry rubber babies, or bumpers for rubber buggies that carry babies.)
- Little Hope Given Brain-Damaged Man (A brain-damaged man is unlikely to recover, or a brain-damaged man is causing another situation to have little hope of resolution, or someone gave a brain-damaged man to a small girl named Hope.)
- Somali Tied to Militants Held on U.S. Ship for Months. (Either the Somali was held for months, or the Somali was just now linked to militants who were held for months. One could also imagine rope was involved, at which point lexical ambiguity comes into play.)
- Free Ireland. (Is it a syntactical entity, a Republican call-to-arms or just an amazingly good deal?)
An example according to Aristotle 
Aristotle writes about an influence of ambiguities on arguments and also about an influence of ambiguities depending on either combination or division of words.
... if one combines the words 'to write-while-not-writing': for then it means, that he has the power to write and not to write at once; whereas if one does not combine them, it means that when he is not writing he has the power to write.
— Aristotle, Sophistical refutations, Book I, Part 4
Aristotle here - probably without knowing this - gives an excellent example of syntactic ambiguity.
He is (writing and not writing)
He (is writing) and not writing.
In the first instance we are deprived of the correct understanding but in the second instance is emphasized literacy as a condition for writing.
My all-time favorite example of syntactic ambiguity comes from Wikipedia: 'Charlotte's Web is a children's novel by American author E. B. White, about a pig named Wilbur who is saved from being slaughtered by an intelligent spider named Charlotte.'
In this example it can be interpreted that the pig named Wilbur either:
- is saved by an intelligent spider named Charlotte from someone else's attempt to slaughter him; or
- is saved by someone else from an intelligent spider named Charlotte's attempt to slaughter him.
See also 
- Garden path sentence
- Ibis redibis
- List of linguistic example sentences
- Natural language processing
- Structural ambiguity
- Transderivational search
- Layman E. Allen "Some Uses of Symbolic Logic in Law Practice" 1962J M.U.L.L. 119, at 120;
- L.E. Allen & M.E. Caldwell "Modern Logic and Judicial Decision Making: A Sketch of One View" in H.W. Baade (ed.) "Jurimetrics" Basic Books Inc., New York, USA, 1963, 213, at 228
- Ben Zimmer, "On Language: Crash Blossoms", New York Times Magazine, January 27, 2010 online text
- Gloria Cooper, ed., Squad Helps Dog Bite Victim, and other flubs from the nation's press, Dolphin Books, 1980, ISBN 0-385-15828-9
- Gloria Cooper, Red tape holds up new bridge, and more flubs from the nation's press, Perigee Books, 1987. ISBN 0-399-51406-6
- 1997 Headlines at Snopes.com.
- Mayes, Ian (2000-04-13). "Heads you win: The readers' editor on the art of the headline writer". London: Guardian. Retrieved 2009-06-05.
- Fritz Spiegl, What The Papers Didn't Mean to Say Scouse Press, Liverpool, 1965