Encyclopedia Britannica and Merriam-Webster have sued OpenAI, claiming the AI company engaged in “massive copyright infringement.”

According to the lawsuit, Britannica, which owns Merriam-Webster—holds copyrights on nearly 100,000 online articles that, it alleges, were scraped and used to train OpenAI’s language models without authorization.

Britannica further claims that OpenAI infringes copyright by producing outputs that include “full or partial verbatim reproductions” of its content and by using its articles in ChatGPT’s RAG (retrieval-augmented generation) system.

The RAG tool allows the language model to search the web or other databases for updated information when answering queries.

Britannica additionally alleges that OpenAI breaches the Lanham Act, a trademark law, by producing fabricated content—so-called “hallucinations”—and falsely attributing them to the publisher.

“ChatGPT starves web publishers like [Britannica] of revenue by generating responses to users’ queries that substitute, and directly compete with, the content from publishers like [Britannica],” the lawsuit reads. Britannica also alleges ChatGPT’s hallucinations jeopardize “the public’s continued access to high-quality and trustworthy online information.”

Britannica is among several publishers and writers taking legal action against OpenAI over copyright concerns.

Other plaintiffs include The New York Times, Ziff Davis (which owns Mashable, CNET, IGN, and PCMag), and over a dozen newspapers across the U.S. and Canada, such as the Chicago Tribune, Denver Post, Sun Sentinel, Toronto Star, and the Canadian Broadcasting Corporation.