Audience is the group of people who read, hear or watch a work; in writing, it is the reader a writer has in mind while composing.
The word comes from Latin audientia, a hearing, from audire, to hear. It first named the act of listening or a formal hearing granted by someone in authority, as in an audience with the king, before it came to mean the listeners and readers themselves. Writers are commonly taught to define their audience first and to fit vocabulary, length and tone to it.
In 📝On Writing Well, William Zinsser takes a different line. Asked who they are writing for, writers should answer that they are writing for themselves. Chasing an imagined reader breeds pretense, while a writer who stays true to their own voice and story gives the reader something real.
Who am I writing for? I am writing for myself. Be true to your own story. The reader gets the gift of who you are.