Watch our videos showing children in the UK using new words. A rucksack (sac à dos) is a bag that you wear on your back. People call it a backpack too. "My school bag's a rucksack and it's always really heavy." Select ratingGive it 1/5Give it 2/5Give it 3/5Give it 4/5Give it 5/5 Average: 5 (1 vote) Rate Tags Level 3 My travel bag is a rucksack. My travel bag is a rucksack. Log in or register to post comments