Marefa is a collaborative Arabic knowledge project launched on February 16, 2007. Its aim is to build an accurate, comprehensive, diverse, open, neutral, and free encyclopedia that anyone can help edit by writing or drawing on sources licensed for reuse. The site reports more than 170,000 substantive articles and over 2.4 million pages containing material, and began by incorporating content from sources that permit republication.

Marefa offers a broad range of ways to explore and contribute to knowledge. Visitors can browse topics alphabetically, consult a style guide, view recent changes, or discover a random page. The homepage features current events, a daily image, an article of the day, and historical events, providing an evolving introduction to subjects across culture, science, history, and more. Community and help sections support participation, while related projects include Marefa Sources, Marefa News, Marefa Data, and a mind map. The organization also provides a mobile app, making its Arabic reference content accessible on phones.