Weekender and duffle bags may be used interchangeably, but they’re not the same. A weekender bag is any bag with enough space for a weekend-long trip. This may come in the form of single-strap duffle bags, a travel backpack, or a tote-style bag.
On the other hand, a duffle bag refers to the bag’s design rather than its size. Duffles are large, cylindrical bags that have a single strap to carry on your shoulder. They may have enough room for a single night, a few days, a week, or longer.