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The knot () is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. The ISO Standard symbol for the knot is kn.〔(【引用サイトリンク】url=http://www.iso.org/iso/catalogue_detail?csnumber=31888 )〕 The same symbol is preferred by the IEEE; kt is also common. The knot is a non-SI unit that is "accepted for use with the SI". Worldwide, the knot is used in meteorology, and in maritime and air navigation—for example, a vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour. Etymologically, the term derives from counting the number of knots in the line that unspooled from the reel of a chip log in a specific time. ==Definitions== ;1 international knot = :1 nautical mile per hour (by definition), : (exactly),〔 : (approximately), : (approximately), : (approximately). is the length of the internationally agreed nautical mile. The US adopted the international definition in 1954, having previously used the US nautical mile (). The UK adopted the international nautical mile definition in 1970, having previously used the UK Admiralty nautical mile ( []). 〔[http://www.mystartsearch.com/web/?type=ds&ts=1421000036&from=smt&uid=WDCXWD5000AAKX-001CA0_WD-WCAYUM79108891088&q=%s]〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Knot (unit)」の詳細全文を読む スポンサード リンク
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