wrong number

noun3

1. •
   A telephone number dialled by mistake, for example, by transposing digits.

   • I am sorry. You have the wrong number. — Oh. Is this 555-8986? — No. This is 555-8689. — Oh. Excuse me! — Okay. Bye. — 2016
2. •
   A telephone call received from an unfamiliar caller, due to a mistake in the number dialled.

   • - Who was that on the phone? - It was just a wrong number.
3. •
   (old-fashioned) An incorrect notion or understanding concerning a person or situation.

   • Codd said . . . when he had her fixed and tested her a few times he would take me up for a ride. "You got the wrong number," I says. "I don't feel flighty." — 1920