'rucksack' originates from German, specifically the word 'Rucksack', where 'Ruck' meant 'back' and 'Sack' meant 'bag'.

'Rucksack' was borrowed directly from German into English in the late 19th century and has remained largely unchanged.

Initially, it meant 'a bag carried on the back', and this meaning has largely remained the same in modern usage.