dilogy

from The Century Dictionary.

• noun In rhetoric: The use of a word or words twice in the same context; repetition, especially for the sake of emphasis. Unnecessary or ill-judged dilogy results in tautology (which see).
• noun Intentional use of an ambiguous expression; the word or expression so used. Ambiguity in a wider sense is called amphiboly or amphibology.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Rhet.), rare An ambiguous speech; a figure in which a word is used an equivocal sense.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Ambiguous or equivocal speech or discourse.
• noun Repetition of a word or phrase.
• noun A series of two related works