ambiguity

Definition:

The multiple meanings, either inentional or unintentional, of a word, phrase, sentence, or passage.

Examples:

“Good,” for example, can mean “useful” or “functional” (//That’s a good hammer//) “exemplary” (//She’s a good student//) “pleasing” (//This is good soup//) “moral” (//He is a good person//)

source: http://en.wikipedia.org/wiki/Ambiguity