At Edmonton’s Animethon 2025, anime director Nobuyoshi Habara (known for Rurouni Kenshin and Gurren Lagann) was stunned to learn that “isekai” has officially entered the Oxford English Dictionary. He shared his surprise and delight, noting that English speakers not only understand the term but that the OED has now recognized it.

Oxford’s Definition Goes Beyond “Another World”

While “isekai” in Japanese literally means “another world,” the OED defines it specifically as a genre of Japanese science or fantasy fiction. In this genre, a protagonist is transported to or reincarnated in a strange or unfamiliar world. The dictionary even cites anime, manga, and video games as examples of media where the term applies.

Cultural Impact of the Isekai Genre

This genre isn’t niche anymore—it’s mainstream. From Sword Art Online to That Time I Got Reincarnated as a Slime, “isekai” has shaped the modern fantasy landscape. Its inclusion in the OED signals the genre’s reach beyond fandom and into broader English-speaking society, recognized as a legitimate storytelling category.

English Speakers Get Creative with “Isekai”

Online, “isekai” has even been adapted as a verb—especially among fans—though this usage hasn’t landed in dictionaries yet. You’ll see quips like “Truck-kun isekai’d the main character into another realm!” It’s amusingly unintended in Japanese, but English speakers embrace the playfulness of bending the term into new forms.