Aichu - Aichu

Japanese: 相（間）中 - あいちゅう

...The third floor was entirely used for the rooms of leading actors, with the zato room at the very end, followed by other rooms according to rank, and a large, spacious room. This large room was used by the lower-ranking actors, called myodaiga and aichiyu, according to their seating order, and had a hearth in the center. In addition to rehearsals, it was also used as a place for rehearsals such as script readings, tsuketate, and general review, from the time of the first performance until the opening day. ...

From [Kabuki]

…Metal "thunder car" may also be used.
[Actor-related terms]
Aichiyu: One of the ranks of actors from the Edo period to the Meiji period. It was also written as "Manaka."

*Some of the terminology explanations that mention "Ai(kanaka)" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…3階はすべて立役の部屋で，いちばんつきあたりに座頭部屋があり，序列によって立役の部屋がつづき，広い空間をもつ大部屋があった。この大部屋は，名題下，相中（あいちゆう）と呼ばれる下座俳優が席次にしたがって雑居し，中央に囲炉裏があった。顔寄せから初日までの間，舞台稽古を除いて，本読み，付立，総ざらいなど稽古を行う場所としても利用された。…