Nya is the Japanese onomatopoeia for a cat's meow, and arigatou is the familiar Japanese word for thank you, so together the phrase reads as a playful, cat-like way of saying thanks. Online, the clip circulates as a short anime-style reaction sound, often paired with cat videos, dance loops and cute character edits where a thank-you moment needs extra charm. Its popularity comes from that simple combination: it is instantly understood even by viewers who do not speak Japanese, and its bubbly tone fits short-form video, streams and memes without needing any context.