when you accidentially dial someone from your mobile phone by having it bang against something.
I accidialed my ex-husband when my phone got thrown into my purse.
to accidentally call someone, or the wrong person, on the telephone.
"Sarah must have accidialed Erica, because Erica does not even like her. If that was not an accidial, then she better loose Erica's number if she knows whats good for her!"
"I was trying to call Kelly A. but I accidialed and called Kelly B."