1. an act or instance of calling out.
  2. an order to report for emergency or special work, especially at an unusual time or place.
  3. a letter, number, or other device for identifying or calling attention to a particular part of an illustration.
  4. a challenge to a duel.

Origin of call-out

First recorded in 1885–90; noun use of verb phrase call out Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018