Mathematical term for a three-dimensional curve winding around a cylinder or cone, like a spring or screw thread.
DNAは二重らせん構造をしている。
DNA has a double helix structure.
Mathematical term for a curve winding around a fixed point while moving outward, like a snail shell or a whirlpool. Cross-referenced with 渦巻き線.
See also: 渦巻き線
This figure is called Archimedes' spiral.
Compound of 螺 (ra, 'snail' or 'spiral') and 線 (sen, 'line'). The exact historical derivation is uncertain, but the spelling is conventionally associated with mathematical curves.