A technique, much like phishing, that allows criminals to maliciously gain access to your personal information for the purposes of identity theft. Vishing scams use a combination social engineering and phishing to find victims that can be tricked into providing credit card or personally identifying information. Typically, the criminal sends the victim some kind of notice or leaves a message, requesting that the victim returns a call to verify an account or some similar ploy. When the victim returns the call, they are asked to provide account and identifying information under the guises of "updating" the account.
Once the criminal has access to that information, it is used for credit card or banking fraud, or as the first step in a stolen identity. Vishing also allows criminals to spoof caller-id, making a vishing scam hard to detect because everything appears to be legitimate.