The term 'Biological Pouch' refers to a SAC-like organ found in some species of marsupials, such as kangaroos and koalas. This pouch is used to carry and protect their young during the early stages of development. The acronym for this term is SAC, which stands for 'specialized abdominal cavity'. This pouch is an adaptation that allows the mother to keep her young safe and secure while she is on the move.