A publication is a single digitalised print edition of your newspaper or magazine.
The print edition with the publication date of, e.g., January first of the year 2000 is called a publication within Prenly. Any separate publication dates are considered to be a publication.
More detailed, a publication within Prenly is a collection of digitalised versions of the physical newspaper spread pages and/or associated simplified content of said spread pages. Or, just digitally written articles.