Updated: 04/26/2017 by Computer Hope

A callout is an explanation in a specific portion of an example or an image to help explain what it is describing (via a line, arrow, or other means). It is often used in publishing such as books, manuals, technical specifications, and other technical materials.

An example of a callout is shown below, where the callout is pointing to a line a JavaScript code to provide additional explanation about that line of code.


In this case, it points to a line of code and offers additional details. A callout could also be used for other purposes, such as labeling parts of a machine in an image.