Refers to a room at the front of a building or a waiting room before a main room; can be used for a parlor or lobby. The gloss 'anticum' is a rare architectural term.
来客は前室でしばらく待たされた。
The visitor was made to wait in the front room for a while.
anterior ventricle
Medical/anatomical term; specifically refers to the anterior ventricle of the brain or heart.
前室は脳の前方に位置する。
The anterior ventricle is located in the front part of the brain.
ホテルの前室で待ち合わせましょう。
Let's meet in the hotel lobby.