Single thread - 1 start thread

…When a screw rotates once around its axis, the thread moves a distance equal to the lead. In addition to single-start threads, which have threads along one parallel spiral, there are also threads with threads along two, three, or generally many parallel spirals; double-start threads, triple-start threads, and double-start and triple-start threads are collectively called multiple-start threads. In a cross section that includes the axis of the screw, the distance parallel to the axis between two corresponding points on adjacent threads is called the pitch; for single-start threads, it is equal to the lead, but for multiple-start threads, it is equal to the lead divided by the number of threads. …

*Some of the terminology explanations that refer to "single start threads" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…ねじを軸のまわりに一回転するとき，ねじ山はリードに等しい距離だけ移動する。　ねじは，1本のつる巻線に沿ってねじ山を作った1条ねじのほか，2本，3本，さらに一般に多数の平行なつる巻線に沿ってねじ山を作ったものがあり，2条ねじ，3条ねじ，あるいは2条ねじ，3条ねじを含めて多条ねじと総称される。ねじの軸線を含む断面において，互いに隣り合うねじ山の相対応する2点間の軸線に平行な距離をピッチpitchといい，1条ねじの場合はリードに等しいが，多条ねじではリードを条数で割ったものに等しい。…

※「１条ねじ」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報