Junior idol

In Japan, a junior idol (ジュニアアイドル, junia aidoru^?), alternatively chidol (チャイドル, chaidoru^?) or low teen idol (ローティーンアイドル, rōtīn aidoru^?), is primarily defined as a child or early teenager pursuing a career as a photographic model. Generally, this means gravure, or "cheesecake", fully clothed shots; but, junior idols can, and some do, eventually enter the AV industry. Child actors, musicians, and J-pop singers (whose musical genre is often termed idol pop) can also be considered junior idols and are often featured in photobooks and image DVDs.

Female fashion models (not to be confused with glamour models, including gravure idols) also begin their careers typically at age 13–15, but are usually not considered junior idols. Child models, whose careers are usually over by their early teenage years, are also not usually considered junior idols.

...
Wikipedia