Is there a term to describe when students are in one classroom for most of the day?
Something close may be a “floating teacher model”.

A room is predominantly occupied by one instructor then another comes in during the primary instructor’s prep period to teach his or her lesson.  There’s no reason one room would be restricted to only two teachers in this practice. “Cart” teachers or “mobile” teachers are also commonly used terms for these roles. While there is research on this practice, I haven’t come across any where all teachers are subject to moving between rooms. That’s not to say a universal term for the structure does not exist.