light novel ラノベ

In Japanese, "light novel," raito noberu ライトノベル, ranobe ラノベ., or LN, is a manga without pictures. That is, they're novels, stories in pure text, that are written in the same style of fiction as manga and anime.

vs. Novels

The difference between a light novel and a novel is pretty simple: light novels are anime.

Light novels often feature fantasy settings and ridiculous stuff the likes you'd see in anime. They often feature tropes you'd see in anime. They make references to anime, like references to anime you'd see in anime. Even the few illustrations they do have, like the cover illustration, is made in anime style. And the characters are designed like anime characters. They're pretty much anime without animation in it.

There's an easy way to understand what light novels are. First, imagine an otaku オタク or a fujoshi 腐女子. Now, imagine they want to draw a doujinshi 同人誌. Now, imagine they can't actually draw that because they don't know how to draw, so they just write instead. There, you know how light novels are made now.

As for other differences, light novels are generally targeted at teenagers and young adults, so the text tends to be easier to read.

Examples

Some examples of light novels include:

Overlord
オーバーロード
An MMORPG addict goes to the MMORPG world.
Re: Zero kara Hajimeru Isekai Seikatsu
re:ゼロから始める異世界生活
An otaku goes to a fantasy isekai.
GATE: Jieitai Kanochi Nite, Kaku Tatakaeri
ゲート自衛隊彼の地にて、斯く戦えり
An army otaku goes to a fantasy isekai.
No Game No Life
ノーゲーム・ノーライフ
A couple of twin otaku hikikomori NEET geniuses go a fantasy isekai.
Sword Art Online
ソードアート・オンライン
A game addict goes to a virtual world.
Yahari Ore no Seishun Rabu Kome wa Machigatteiru
やはり俺の青春ラブコメはまちがっている。
A loser no-friends extremely anti-social high-schooler is forced to join a club.
Suzumiya Haruhi no Yuuutsu
涼宮ハルヒの憂鬱
A guy who doesn't believe in aliens, time-travelers, or espers gets a girlfriend who does.

Origin

The word light novel is a wasei-eigo 和製英語. It's a Japanese word made out of English words. As such, "light novel" doesn't mean anything in English. It only means something to weebs who know what a light novel is in Japanese.

Web Novels, WB

While most light novels, LN, are published on paper, serialized, some light novels are not. Just like One Punch Man ワンパンマン started out as a very, very ugly web comic, which was miraculously turned into a gorgeous manga, and then into an amazing anime, some light novels follow the same path.

Such is the case of Re: Zero kara Hajimeru Isekai Seikatsu re:ゼロから始める異世界生活, for example, which was first published online as a web novel, then tidied up and adapted as a light novel, then drawn and adapted as a manga, and then animated and adapted as an anime.

You can even read the Re:Zero web novel in Japanese right now if you want, all thanks to the wonders of the internet.