The prefix “r/” begins subreddit names on Reddit.
It is placed before a community’s name to identify that name as a Reddit community—for example, r/worldnews, r/science, or r/gaming. Reddit’s own terminology explains “r/” as an abbreviation connected with Reddit, and the format became a familiar shorthand across the web.
The prefix is part of Reddit’s address and naming convention, not usually part of the community’s ordinary spoken name. Someone may say “the World News subreddit” while writing “r/worldnews.” The same notation also appears in links and references to communities.
Readers sometimes confuse “r/” with “u/.” The former points to a subreddit or community; the latter precedes a Reddit username, such as u/spez. A post or comment inside a subreddit is a separate object and does not itself receive the “r/” prefix. Reddit increasingly uses “community” in official language, but the r/ convention remains standard in Reddit-style writing.