Wikipedia:Project namespace

Namespaces
Subject namespaces Talk namespaces
0 (Main/Article) Talk 1
2 User User talk 3
4 Wikipedia Wikipedia talk 5
6 File File talk 7
8 MediaWiki MediaWiki talk 9
10 Template Template talk 11
12 Help Help talk 13
14 Category Category talk 15
100 Portal Portal talk 101
118 Draft Draft talk 119
710 TimedText TimedText talk 711
828 Module Module talk 829
Former namespaces
108 Book Book talk 109
442 Course Course talk 443
444 Institution Institution talk 445
446 Education Program Education Program talk 447
2300 Gadget Gadget talk 2301
2302 Gadget definition Gadget definition talk 2303
2600 Topic 2601
Virtual namespaces
-1 Special
-2 Media
Current list (API call)

The project namespace or Wikipedia namespace is a namespace consisting of administration pages with information or discussion about Wikipedia. Pages in this namespace will always have the prefix Wikipedia:. They can also be reached by alias WP: or the standard (for any MediaWiki site) prefix Project:. Its namespace number is four (4).