Where does “booksack” come from?

booksack (English) comes from English Sack, from Middle English sak, from Old English sacc, from Old English sæcc, from Proto-West Germanic sakku, from Proto-Germanic sakkuz, from Latin saccus, from Ancient Greek σάκκος — sack; sackcloth; sackcloth vestment, penitential...

Ancestry of “booksack”, step by step

booksack traces back through two separate lines of ancestry.

via English Sack

StepLanguageWordMeaning
1EnglishSackA bag; especially a large bag of strong, coarse material for storage and handling of various commodities, such as potatoes, coal, coffee; or, a bag with handles used at a supermarket, a grocery sack; or, a small bag for small items, a satchel
2Middle Englishsakbag, sackcloth
3Old Englishsaccsack, bag
4Old Englishsæccbattle, strife, fighting
5Proto-West Germanicsakkusack, bag
6Proto-Germanicsakkuzsack, bag, purse
7Latinsaccussack, bag; purse, wallet, moneybag; garment of...
8Ancient Greekσάκκοςsack; sackcloth; sackcloth vestment, penitential...

via English Book

StepLanguageWordMeaning
1EnglishBookthe Bible
2Germanbūchbook collection of sheets of paper bound together to hinge at one edge; long work fit for publication
3Middle High Germanbuoch
4Old High Germanbuohbook
5Proto-Germanicbōk
6Proto-Germanicbakanąto bake
7Proto-Indo-Europeanbʰeh₃g-to bake, to roast, to fry
Every word from Ancient Greek σάκκοςEvery word from Latin saccusEvery word from Proto-Germanic sakkuz
booksack — Etymology, Origin & Word History | Etymology Explorer