螺旋(らせん)

らせん
noun
spiral; helix
sciencedescriptive
1. spiral; helix; coil
A curve that winds around a centre or an axis, like a snail's shell, a coiled spring or a spiral staircase. The kanji are rare, so it is usually written in kana: らせん or ラセン.
螺旋(らせん)階段(かいだん)を上(のぼ)る。
To climb a spiral staircase.
DNAは二重(にじゅう)らせんの形(かたち)をしている。
DNA has the shape of a double helix.
鳥(とり)たちは上昇気流(じょうしょうきりゅう)に乗(の)って、らせんを描(えが)きながら空高(そらたか)く昇(のぼ)っていった。
Riding the updraft, the birds rose high into the sky in spirals.

The kanji form appears in print and on signs (螺旋(らせん)階段(かいだん)), but kana is the everyday spelling. For a figurative downward spiral, Japanese says 負(ふ)のスパイラル or 悪循環(あくじゅんかん) rather than らせん.

Common expressions

Related words

  • 渦(うず): whirlpool, swirl — a spiral in a flat plane or in water
  • ねじ: screw — its thread is a spiral

Related Words

Related: 渦(うず) (whirlpool, swirl)
Related: ねじ (screw)
general
Added 2026.9.29 1:36 · Revised 2026.9.29 1:39
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