duffel bag        
noun [ C ] (also duffle bag) uk/ˈdʌf.əl ˌbæɡ/ us/ˈdʌf.əl ˌbæɡ/
 UK圆筒包,收口提袋 
a tube-shaped cloth bag with a circular bottom and a thick string at the top that is used to close it and carry it
  US圆筒形旅行包 
a long bag used for carrying clothes, etc. when you are travelling