Reserved Page Names
Certain pages names (used in permalinks) are reserved for use by either WordPress or the theme and content model and should not be used as the single-word titles of any page at any level.
Reserved page names include:
posts
pages
media
people
publications
facilities
research
courses
documents
tribe-events
categories
tags
format
people_types
organizations
subject_areas
facility_types
services
student_types
publication_types
workflow_states
feed
atom
rss
json
In addition to these, WordPress will not allow page URLs containing only numbers, since it uses numeric URLs to distinguish posts from pages and would incorrectly try to parse the numeric URL as a date. If you have a page titled with a number, e.g. 2006
, WordPress will automatically change its generated URL to page-2006
. You may edit the URL directly to something more appropriate, e.g. 2006-archives
.