1. A return phone call. (In each of these usages, the term can be spelled "call-back.") I finally got a callback from the doctor's office with my test results this morning. This is an automated call-back service letting you know that your pizza is on its way.

2. An instruction to return to work, as after a layoff or suspension. Union officials are trying to secure a call-back for every factory worker affected by the layoff. The callback could see up to 2,000 government workers returning to work despite the government shutdown.

3. A recall made by a manufacturer of a defective product. If that part does in fact cause engines to overheat, then we're going to have to do a massive callback.

4. A follow-up audition or interview, as when pursuing an acting role or applying for a job. After months of fruitless auditions, I finally got a callback! I'm so excited that I don't even care that it's for an ointment commercial! I just got a call-back from the recruiter—she wants me to come in for a second interview!

5. A reference to a past scene or plot development, as in a TV show. The Gilmore Girls revival was full of callbacks to the original series.

6. In comedy, a joke that references an element used in a joke told earlier in the routine. The callback that I've been using at the end of my set is really killing. The comedy show loves to feature call-backs to jokes in previous sketches.