Aback adv. : Toward the back or rear; backward.

Aback adv. : Behind; in the rear.

Aback adv. : Backward against the mast; -- said of the sails when pressed by the wind.

Aback n. : An abacus.

Example:
Are any of you taken Aback by all the McCain and Palin lies?

Taxonomy
aback, Merriam-Webster Online Dictionary, Dictionary, webster, Word Games, Webster Online Dictionary with audio pronunciations, glossary, english, language, ESL, adverb, 12th century, catch the wind, sail, surprise, retort, Unabridged Dictionary, Search Boxes.

Defination from the web:
aback from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... See a map of "aback" in the Visual Thesaurus. Pronunciation Symbols. Share this entry: Link to this page: Cite this page: Products. Premium ...