Definition - What does Subreddit mean?
Subreddits are subsidiary threads or categories within the Reddit website. They allow users to focus on a specific interest or topic in posting content that gets voted up or down by relevance and user preference.
Techopedia explains Subreddit
In the early years of the millennium, two University of Virginia students created the Reddit website. Reddit quickly took off as a way to present content to a community of users. Its unique logo and style as well as its system of parliamentary content rating make it a prominent part of the Internet landscape.
Within the general Reddit site, various subreddits point people toward areas of the site that correspond to their interests. For example, there may be a subreddit for holidays, one for pictures of family and friends, or one for political commentary. Some subreddits also accommodate particular goals for example, where people may ask people to Photoshop or alter supplied photos.