Ambiguity or fallacy of ambiguity is a word, phrase, or statement which contains more than one meaning.

Ambiguous words or statements lead to vagueness and confusion, and shape the basis for instances of unintentional humor. For instance, it is ambiguous to say “I rode a black horse in red pajamas,” because it may lead us to think the horse was wearing red pajamas. The sentence becomes clear when it is restructured “Wearing red pajamas, I rode a black horse.”

Similarly, same words with different meanings can cause ambiguity e.g. “John took off his trousers by the bank.” It is funny if we confuse one meaning of “bank” which is a building, to another meaning, being “an edge of a river”. Context usually resolves any ambiguity in such cases.

Although ambiguity is considered a flaw in writing, many writers use this technique to allow readers to understand their works in a variety of ways, giving them depth and complexity. Let us analyze some ambiguity examples in literature.

“The Sick Rose”, a short lyric written by William Blake, is full of ambiguities:

“O Rose thou art sick.
The invisible worm,
That flies in the night
In the howling storm:
Has found out thy bed
Of crimson joy;
And his dark secret love
Does thy life destroy”

Many of the words in the above lines show ambiguity. We cannot say for sure what “crimson bed of joy” means; neither can we be exact about the interpretation of “dark secret love”. The ambiguous nature of such phrases allows readers to explore for deeper meanings of the poem.

Some of those who have analyzed this poem believe that “Has found out thy bed, Of crimson joy” refers to making love.

Ambiguity in literature serves the purpose of lending a deeper meaning to a literary work. By introducing ambiguity in their works, writers give liberty to the readers to use their imagination to explore meanings. This active participation of the readers involves them in the prose or poetry they read.

 http://literarydevices.net/ambiguity/