Oxford Advanced American Dictionary

Definition of rucksack noun from the Oxford Advanced Learner's Dictionary

rucksack

noun
rucksack pronunciation English ˈrʌksæk rucksack pronunciation American ˈrʌksæk
(British English) (also backpack North American English, British English)
 
a large bag, often supported on a light metal frame, carried on the back and used especially by people who go climbing or walking