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knapsack [knapsack 词源字典]: knapsack: [17] The -sack of knapsack is no doubt essentially the same word as English sack, but the knap- presents slightly more of a problem. The term was borrowed from Low German knappsack, and so probably knapprepresents Low German knappen ‘eat’ – the bag having originally been named because it carried a traveller’s supply of food.
[knapsack etymology, knapsack origin, 英语词源]
knap (v.): "to strike with a sharp sound," late 15c., echoic. Earlier (c. 1400) as a noun meaning "abrupt stroke." Related: Knapped; knapping.
knapsack (n.): c. 1600, from Low German Knapsack (Dutch knapzak), probably from knappen "to eat" literally "to crack, snap" + Sack "bag" (see sack (n.1)).
knave (n.): Old English cnafa "boy, male servant," common Germanic (cognates: Old High German knabo "boy, youth, servant," German knabe "boy, lad," also probably related to Old English cnapa "boy, youth, servant," Old Norse knapi "servant boy," Dutch knaap "a youth, servant," Middle High German knappe "a young squire," German Knappe "squire, shield-bearer"). The original meaning might have been "stick, piece of wood" [Klein]. Sense of "rogue, rascal" first recorded c. 1200. In playing cards, "the jack," 1560s.
knob (n.): late 14c., knobe, probably from a Scandinavian or German source (compare Middle Low German knobbe "knob," Middle Dutch cnoppe, Dutch knop, Old Frisian knopp, knapp, Old High German knopf, German Knopf "button," Old Norse knyfill "short horn"). Meaning "knoll, isolated round hill" is first recorded 1640s, especially in U.S.