If you're looking for a word that means the same thing as suitcase, you might be interested in the word luggage. Luggage is a general term that can refer to any type of bag or container used for carrying personal belongings, whether it's a small carry-on bag or a large suitcase.
Suitcases are just one type of luggage, and they tend to be larger in size than other types of bags like backpacks or duffel bags. They usually have handles and wheels for easy transport, and they're often used for travel since they can hold a lot of items.
So if you need a word to describe a piece of luggage that's smaller than a suitcase, you might use the word bag. And if you need a word to describe something even larger than a suitcase, you could use the word trunk.