A haversack is a canvas bag that is usually worn over one shoulder.
[mainly British]
haversack in British English
(ˈhævəˌsæk)
noun
a canvas bag for provisions or equipment, carried on the back or shoulder
Word origin
C18: from French havresac, from German Habersack oat bag, from Old High German habaro oats + Sacksack1
haversack in American English
(ˈhævərˌsæk)
noun
a canvas bag for carrying rations, etc., generally worn over one shoulder, as by soldiers or hikers
Word origin
Fr havresac < Ger habersack, lit., sack of oats < haber (now hafer < LowG), akin to E dial. haver, oats (? orig. “goat food” < IE base *kapro- > L caper, goat) + Ger sack, sack1