Is thesis considered a publication? Yes, but a very special kind of publication. Copies of theses are usually kept in department and university-wide libraries, but not published as such in professional journals. Their form and content are not the same as that of a journal article, or a book for that matter.

Is a thesis published or unpublished?

A dissertation or thesis is considered published when it is available from a database such as ProQuest Dissertations and Theses Global or PDQT Open, an institutional repository, or an archive.

Is thesis considered as a publication?

A thesis is not published, under that definition. Nonetheless, an unpublished thesis needn't be private, e.g., it may appear online and it may be available in university library.