Nagoya –

Do the words “dōtankyohi” (同担拒否) or “irukatsu” (イル活) mean anything to you? Perhaps you’ve stumbled upon them on the internet and, squinting, closed the window.

There are, however, people for whom these terms serve as a vital way to engage with friends and fellow fans — or otaku — about their favorite idols, games, anime or other beloved media.

A new book is trying to bridge the knowledge gap: “Otaku Dictionary Daigenkai,” out Tuesday from publisher Sanseido, catalogs and defines lingo widely used among several fandoms.

The book was originally created as a student seminar project at Nagoya College. Twelve female students, led by their professor, Yoshiko Koide, an expert in Japanese linguistics, went deep into the otaku worlds they were personally a part of.

“Otaku Dictionary Daigenkai” is broken up into 14 chapters, including one for catch-all otaku terms, idol culture and games like Arknights, Splatoon and Pokemon. It also includes chapters for “two-dimension” (manga and anime), “three-dimension” (real life people) and “2.5-dimension” (musicals in which real life people act out two-dimensional media).

Koide stresses that the book is not intended as comprehensive or authoritative reference material but rather a record of the students’ authentic passions for their various “oshi” (the subject of one’s fandom). As a class, they sought to capture how the words are used “natively” by genuine speakers of the various otaku “languages.”

The entries range from general and self explanatory to so niche you may find yourself in a deep internet rabbit hole trying to understand them. Here are a few words we picked out from “Otaku Dictionary Daigenkai” to help you in your otaku endeavors:

Oshi (推し): (filed under: common otaku words) The noun for supporting — or “osu” (推す) — someone or something. Used to describe the target of a fan’s intense love and support, to the extent that they expend their own energy to see the person or thing succeed.

“I’m happy today because I have my oshi. (The fact of their existence alone makes me happy.)”

Tantō (担当): (filed under: three-dimensional) A real-life figure that fans sees themselves as being “in charge of” — can also refer to the fans themselves. The fan feels they have more responsibility than with mere “oshi,” in that they must help the person grow into becoming a better talent.

“My tantō is going to be on the front cover of a magazine this month so I need to buy 10 copies of it.”

Dōtan (同担): (filed under: common otaku words) The act of having the same tantō as someone else, or that person themselves. In K-pop fandom, known as dōpen (同ペン). In some cases, a fan may actively reject sharing their tantō with others, which is referred to as dōtankyohi (同担拒否).

“I did otakatsu (オタ活) (the act of doing otaku activities) with my dōtan friend today. I’m so glad she’s not dōtankyohi.”

Irukatsu (イル活): (filed under: K-pop) Refers to when K-pop idols are active in Japan (“ilbon” in Korean). When a K-pop idol holds a concert in Japan, it’s known as irukon (イルコン) — short for ilbon concert — and debuting in Japan is known as irude (イルデ) — ilbon debut.

“I’m so happy Le Sserafim is doing more irukatsu — I’ve been really looking forward to seeing them live in Japan.”

TMI: (filed under: K-pop) Abbreviation for “too much information.” Used in English-speaking countries in general usage, but used within Japan and Korea’s K-pop fandom to describe when idols share irrelevant information about their personal life.

“Huh Yun-jin telling her TMI of the day during her livestream was so cute.”

Cup holder (カップホルダー): (filed under: K-pop) Cup sleeves that are made — often by K-pop fans — featuring their favorite idol, which are handed out at cafes for events like the idol’s debut or their birthday.

“I’m so sad that they were out of Lee Heeseung’s cup holder by the time I arrived at the cafe.”

Aotenjō (青天井): (filed under: common game terms) The sky, or to spread limitlessly like the sky. Used to describe when a gacha (ガチャ) — a drawing system in games that is used by players to win an item or character at random — in a game is limitless and feels like it’s impossible for the player to win the item or character they want. Given the danger that players will continue to excessively kakin (課金) — spend money — they must be careful.

“I’m not going to play a game where the gacha is aotenjō.”

Kusogē (クソゲー): (filed under: common game terms) A game that sucks, whether because it’s impossible to clear or because it has poor game design.

“I hate the advertisements for all these kusogē.”

Bacon lettuce (ベーコンレタス): (filed under: BL) A euphemism for “boys love,” a genre of media that features romantic and sexual relationships between male gay couples. Referred to as such because “bacon lettuce” shares the same first letters as “boys love.”

“Boys love? You mean bacon lettuce?”