noun
karaoke box; karaoke room
A private room in a karaoke establishment that can be rented by the hour, typically with a karaoke machine, seating, and food/drink service.
週末は友達とカラオケボックスに行く。
On weekends, I go to a karaoke box with friends.
あのカラオケボックスは部屋が広くてきれいだ。
That karaoke box has spacious and clean rooms.
Variant with interpunct; less common in everyday writing.
Refers to karaoke in general or the activity; カラオケボックス specifically means the private-room venue.
Wasei-eigo compound from カラオケ (karaoke) + ボックス (box), referring to a box-like private room for karaoke.