"Multiple sessions, switching between them" is multiplexing. "Kept open, persisting" is orthogonal, I agree. The parent said "tiling" and I assume they were r

"Multiple sessions, switching between them" is multiplexing. "Kept open, persisting" is orthogonal, I agree. The parent said "tiling" and I assume they were referring to, well, tiling - putting multiple non-overlapping windows on the screen at the same time by dividing up the available space.