What is a name used by an author instead of his real name?

The name used by an author instead of their real name is called a pen name, pseudonym, or nom de plume.

Here are some examples:

* Pen name: J.K. Rowling (real name: Joanne Rowling)

* Pseudonym: Mark Twain (real name: Samuel Clemens)

* Nom de plume: George Eliot (real name: Mary Ann Evans)

Authors use pen names for various reasons, including:

* Privacy: To protect their personal life.

* Branding: To create a distinct identity for their work.

* Genre separation: To write in different genres without associating their name with all of them.

* Marketing: To appeal to a specific audience.

* Social or political reasons: To avoid persecution or censorship.