The word "duffles" is commonly used to refer to large cylindrical bags that are used to store and carry belongings. However, there are several synonyms for the word that can be used interchangeably. One such synonym is "kitbag", which is often used in military settings to refer to similar bags used to store a soldier's kit. "Holdall" is another synonym that is often used to refer to larger bags that are carried by hand. "Tote" and "carryall" are also common synonyms that are used to refer to similar bags. Finally, "sack" can also be used to refer to a large bag used for holding belongings.