There are escape slides, life rafts & slide rafts. The 1st, slide, is as per Scribble says. A life raft is an independent item stored on board and needs to be launched. A slide raft is an escape slide that can then be detached and can be used as a raft with much more protection for pax. In my day the large ETOPS a/c were fitted with slide rafts. Whether that was an XAA requirement or a manufacturer design I do not know, but the ETOPS regs must have come into play.