A traditional definition:
pubˇlish ... To prepare and issue (printed material) for
public distribution or sale. 2. To bring to the public
attention; announce. 1. To issue a publication. 2.
To be the writer or author of published works or a work.
A modern definition:
An individual or organization involved in the publication and
dessemination of material. The technology of the WWW has
broadened the ability of individuals to self-publish material in
an economical fashion that has never been possible before.