A pen name is a fake name that a writer uses instead of their real name when publishing their work. Samuel Clemens wrote his famous novels about Tom Sawyer and Huckleberry Finn under the pen name Mark Twain. Theodor Geisel became beloved as Dr. Seuss. Mary Ann Evans used the pen name George Eliot because publishers in the 1800s often wouldn't take female authors seriously.

Writers choose pen names for many reasons. Some want privacy and don't want strangers showing up at their house after reading their books. Some write in different genres and use different names to keep them separate: a serious mystery author might use a pen name when writing funny children's books. Some just think their real name sounds boring or hard to remember, while their pen name sounds catchier.

You might also hear it called a pseudonym (SOO-duh-nim), or a nom de plume (NAHM duh PLOOM). When you see “writing under the name of” or “also known as” on a book cover, that's often a clue that you're looking at a pen name rather than the author's real one.