What is the meaning of Callout?

An outgoing telephone call.

An instance of being summoned to visit a certain place in order to provide assistance; an instance of summoning someone who is on call.

A meeting or rally held in order to find interested participants, e.g. for an activity or sports team.

An invitation to fight.

A request for people to join or take part.

A pull quote: an excerpt from an article (such as in a news magazine) that is duplicated in a large font alongside the article so as to grab a reader's attention and indicate the article's topic.

An annotation that pertains to a specific location in a body of text or a graphic, and that is visually linked to that location by a mark or a matching pair of marks.

The act of calling out from work, i.e. announcing that one cannot attend; the act of calling in sick.

A form of verbal abuse with the intention of making the victim feel guilty.

The invocation of an external third-party component.

Source: wiktionary.org