A blog is a website where entries are made in journal style and displayed in a reverse chronological order.

Blogs often provide commentary or news on a particular subject, such as food, politics, or local news; some function as more personal online diaries. A typical blog combines text, images, and links to other blogs, web pages, and other media related to its topic. Most blogs are primarily textual although some focus on photographs (photoblog), videos (vlog), or audio (podcasting), and are part of a wider network of social media.

The term "blog" is a contraction of "Web log." "Blog" can also be used as a verb, meaning to maintain or add content to a blog.