Entries linking to rucksack
Middle English rigge, from Old English hrycg "back of a man or beast," probably reinforced by Old Norse hryggr "back, ridge," from Proto-Germanic *hruggin (source also of Old Frisian hregg, Old Saxon hruggi, Dutch rug, Old High German hrukki, German Rücken "the back"). OED says "of uncertain relationship;" Pokorny, Boutkan, and Watkins have it from PIE *kreuk-, extended form of root *sker- (2) "to turn, bend."
The original "back" sense, predominant in Middle English, seems to have become archaic 17c. Also in Old English, "the top or crest of anything," especially when long and narrow, based on resemblance to the projecting part of the back of a quadruped, the "ridge" of the backbone. Probably also in late Old English "a long elevation of land, a long, narrow range of hills," implied in place-names. From late 14c. of the highest part of the roof of a building, also the strip of ground thrown up between two plowed furrows. The spelling with -dg- is from late 15c.
Ridge-runner, somewhat derisive term for "Southern Appalachian person, hillbilly," especially an upland white farmer of the Ozarks region, is recorded by 1917 (it later came into use in other regions). Also "person who wanders from place to place," often with a suggestion of illicit intent (1930).
"large oblong bag," Middle English sak, from Old English sacc (West Saxon), sec (Mercian), sæc (Old Kentish) "large cloth bag," also "sackcloth," from Proto-Germanic *sakkiz (source also of Middle Dutch sak, Old High German sac, Old Norse sekkr, but Gothic sakkus probably is directly from Greek), an early borrowing from Latin saccus (also source of Old French sac, Spanish saco, Italian sacco), from Greek sakkos "bag (made of goat hair); sieve; burlap, large burlap cloak," which is from Semitic (compare Hebrew, Phoenician saq "sack, cloth of hair, bag, mourning-dress").
The wide spread of this word for "a bag" probably is due to the incident in the Biblical story of Joseph in which a sack of corn figures (Genesis xliv). In English, the meaning "a sack or sack material used as an article of clothing" as a token of penitence or mourning is from c. 1200. The baseball slang sense of "a base" is attested from 1913.
The slang meaning "bunk, bed" is by 1825, originally nautical, hence many slang phrases, originally nautical, such as sack duty "sleep;" the verb meaning "go to bed" is recorded from 1946. Sack-race (n.) is attested from 1805.
also *ker-, Proto-Indo-European root meaning "to turn, bend."
It forms all or part of: arrange; circa; circadian; circle; circuit; circum-; circumcision; circumflex; circumnavigate; circumscribe; circumspect; circumstance; circus; cirque; corona; crepe; crest; crinoline; crisp; crown; curb; curvature; curve; derange; flounce (n.) "deep ruffle on the skirt of a dress;" krone; ring (n.1) "circular band;" ranch; range; ranger; rank (n.) "row, line series;" research; recherche; ridge; rink; rucksack; search; shrink.
It is the hypothetical source of/evidence for its existence is provided by: Latin curvus "bent, curved," crispus "curly;" Old Church Slavonic kragu "circle;" perhaps Greek kirkos "ring," koronos "curved;" Old English hring "ring, small circlet."