Japan’s public TV channel NHK explained at its morning news what “JS” on the online forum means.
NHK introduced this “JS” [J] as a new trend word listed by International Tokyo Toy Show 2012, which means “today’s elementary school girls who are fashion-conscious”, where “JS” comes from “Joshi Shogakusei”(elementary school girls).
Actually the word “JS” as elementary school girls has been used on the Japanese web for years, mainly anonymous online forum represented by 2-channel, and adults who used social network communities as a place to meet under age girls.
In the same way, JC is a junior high-school girl (Joshi Chugakusei), JK = a high-school girl (Joshi Koukousei) and JD = a college girl (Joshi Daigakusei).
|web jargon||full Japanese||meanings|
|JS||Joshi Shogakusei||elementary school girl|
|JC||Joshi Chugakusei||junior-high school girl|
|JK||Joshi Koukousei(abbrev. Joshi-kousei)||high school girl|
|JD||Joshi Daigakusei(abbrev. Joshi-daisei)||college girl|
Caution is that JK has another meaning on the Japanese web, Joushikitekini Kangaete (=from a common sense standpoint. also spoken “Jou-Kou” by taking first Chinese letters) and this usage is as much popular as high-school girl so you need to read the context. (Wikipedia Japanese [J])