Take characters everyone knows, put them in a situation their author never wrote, and post the result for other fans. That is fanfiction — "fanfic" or just "fic". It ranges from hundred-word jokes to novels longer than the series that inspired them, and its best archives hold millions of works.
The instinct is ancient: retelling other people's stories is how storytelling worked for most of human history. The internet just gave it a filing system.
The vocabulary, quickly
Canon — what officially happened in the original. AU (alternative universe) — same characters, different world: the coffee-shop AU is a genre of its own. Ship — a relationship fans want to see; slow burn — that relationship, delayed as long as humanly possible. OC — an original character added to the cast. Crossover — two universes sharing one story. Most of this slang has leaked into general book talk — we covered the wider dictionary in reading slang explained.
Is it legal?
Characters and worlds are protected by copyright; free, non-commercial fanfiction lives in a broadly tolerated space, and most rights holders leave it alone — many quietly value it as proof of a living fandom. The line is money: selling fanfiction of protected work is a real problem. Public-domain sources are the exception — anyone may publish, even commercially, a story built on public-domain characters. A surprising amount of respected literature is exactly that.
Why it trains writers so well
The blank-page problem is pre-solved. Characters, world and voice already exist, so all practice goes into scenes, dialogue and pacing. Feedback is immediate. Readers comment within hours, chapter by chapter — the fastest feedback loop any beginning writer can get. Serialisation teaches structure. Posting weekly teaches cliffhangers, chapter shape and deadline discipline better than any course. The same skills transfer directly when you move to original work — a jump we mapped in how to write a book with no experience.
When you are ready for your own world
Many writers reach a point where the borrowed world starts to feel small — the story they want needs characters nobody else owns. That jump is smaller than it looks: keep the serial habit, keep the feedback loop, swap the universe for yours. For dedicated fanfiction, archives built for it (like AO3) remain the right home; for original serialised fiction, Arwy gives you chapter-by-chapter publishing, comments in the margins, and readers who are there for new worlds — here is how publishing works.
Ready to write something entirely yours? Arwy is on Google Play.