I'm polishing my last but one assignment for submission; trying to lose another 76 words to bring me within the correct word count and make sure all the words are polished and correct. (I noticed that on the second line I had misspelled 'cheeks' as 'checks'. That has got through about a million drafts and at least three other readers, and obviously the spellchecker wouldn't pick it up, so I'm being supercareful.)
Anyway, I just looked up 'rucksack', to make sure it was totally definitely right. And what do I see but the derivation of the word? It's German, and I love German. Rücken is German for back (ruck is German dialect); Sack German for bag. Rucksack = back bag.
I love words. Languages. Cross fertilisation.
Back to the grindstone for now, though.