diff --git a/54.md b/54.md
index fe46918..b2815d7 100644
--- a/54.md
+++ b/54.md
@@ -33,6 +33,7 @@ The content should be Markdown, following the same rules as of [NIP-23](23.md),
   - `title`: for when the display title should be different from the `d` tag.
   - `summary`: for display in lists.
   - `a` and `e`: for referencing the original event a wiki article was forked from.
+  - `c`: for the wiki category.
 
 One extra functionality is added: **wikilinks**. Unlike normal Markdown links `[]()` that link to webpages, wikilinks `[[]]` link to other articles in the wiki. In this case, the wiki is the entirety of Nostr. Clicking on a wikilink should cause the client to ask relays for events with `d` tags equal to the target of that wikilink.
 
diff --git a/README.md b/README.md
index ffa6393..c33855e 100644
--- a/README.md
+++ b/README.md
@@ -233,6 +233,7 @@ Please update these lists when proposing NIPs introducing new event kinds.
 | `p`               | pubkey (hex)                         | relay URL, petname              | [01](01.md), [02](02.md)              |
 | `a`               | coordinates to an event              | relay URL                       | [01](01.md)                           |
 | `d`               | identifier                           | --                              | [01](01.md)                           |
+| `c`               | category                             | --                              | [54](54.md)                           |
 | `g`               | geohash                              | --                              | [52](52.md)                           |
 | `i`               | identity                             | proof                           | [39](39.md)                           |
 | `k`               | kind number (string)                 | --                              | [18](18.md), [25](25.md), [72](72.md) |