Complex sentence: The word peristome is derived from the Greek peri "around, about" and stoma,'mouth', and is a term used to describe various structures in plants or invertebrate animals such as molluscs that surround an opening to an organ.
Split into simpler sentences: The word peristome is derived from the Greek "peri", meaning'around' or'about', and "stoma",'mouth'. It is a term used to describe various structures in plants and invertebrate animals, such as molluscs, that surround an opening to an organ.