idiosyncracy

Usage notes

 * This spelling is commonly considered a misspelling; etymologically the preferred spelling is idiosyncrasy, which is also the only spelling given by most dictionaries, such as the Dictionary.com Unabridged and the American Heritage Dictionary. This spelling is mentioned in the Oxford English Dictionary's entry for idiosyncrasy, but is marked as erroneous. Webster's Third New International Dictionary gives both spellings, but under the entry name idiosyncrasy.