This template is for use on category pages to refer to the primary section within an article associated with this category, which most of the time describes the entire set containing the category.
{{Category main section|article|section}}
The parameter |article=no
changes "in the article" to "on the page" if the main page for the category is not an article.
{{Category main section|article|section|article=no}}
Using {{Category main section|Mathematics|History}}
produces the following result