A writer is anyone who creates a written work, although the word usually designates those who write creatively or professionally, as well as those who have written in many different forms. The word is almost synonymous with author, although somebody who writes, for example, a laundry list, could technically be called the writer of the list, but not an author. Skilled writers are able to use language to portray ideas and images, whether fiction or non-fiction.
A writer may compose in many different forms including (but certainly not limited to) poetry, prose, or music. Accordingly, a writer in specialist mode may rank as a poet, novelist, composer, lyricist, playwright, mythographer, journalist, film scriptwriter, etc. (See also: creative writing, technical writing and academic papers.)
Writers' output frequently contributes to the cultural content of a society, and that society may value its writerly corpus -- or literature -- as an art much like the visual arts (see: painting, sculpture, photography), music, craft and performance art (see: drama, theatre, opera, musical).