knotyoudaoicibaDictYouDict[knot 词源字典]
knot: [OE] The word knot goes back ultimately to a prehistoric Germanic *knūdn-, whose underlying meaning was ‘round lump’. This only emerged in the English word (in such senses as ‘point from which a branch has grown’) in the Middle English period, but it can be seen in knoll [OE], which is a derivative of the same base (the related German knolle means ‘lump’). Knob [14] may be related too, although this has never been conclusively demonstrated.

The Germanic form diversified into English and Dutch knot, German knoten, Swedish knut, and Danish knode (whose Old Norse ancestor knútr was borrowed into Russian as knut ‘whip’, acquired by English as knout [18]). Knit [OE], which originally meant ‘tie in knots’, was derived in prehistoric West Germanic from knot.
=> knit[knot etymology, knot origin, 英语词源]
knot (n.)youdaoicibaDictYouDict
Old English cnotta "intertwining of ropes, cords, etc.," from Proto-Germanic *knuttan- (cognates: Low German knütte, Old Frisian knotta "knot," Dutch knot, Old High German knoto, German Knoten, perhaps also Old Norse knutr "knot, knob"). Figurative sense of "difficult problem" was in Old English (compare Gordian knot). Symbolic of the bond of wedlock, early 13c. As an ornament of dress, first attested c. 1400. Meaning "thickened part or protuberance on tissue of a plant" is from late 14c.

The nautical unit of measure of speed (1630s) is from the practice of attaching knotted string to the log line. The ship's speed can be measured by the number of knots that play out while the sand glass is running.
The distance between the knots on the log-line should contain 1/120 of a mile, supposing the glass to run exactly half a minute. [Jorge Juan and Antonio de Ulloa, "A Voyage to South America" 1760]
Hence the word knot came also to be used as the equivalent of a nautical mile (in pre-WWII use in U.S. and Britain, 6,080 feet). A speed of 10 knots will cover ten nautical miles in an hour (equivalent to a land speed of about 11.5 mph).
knot (v.)youdaoicibaDictYouDict
"to tie in a knot," mid-15c., from knot (n.). Related: Knotted (late 12c.), knotting.