How to say "staircase" in Japanese

• 階段かいだんJLPT N5approx.Common
  nounThe general word for a staircase: a flight of stairs in a house, office or station. It covers 'stairs', 'stairway' and 'staircase' alike, and is what you want for the stairs in a building.
  その階段かいだんを上のぼってはいけません。↗

  You must not go up the stairs.
• だんだんJLPT N1approx.Common
  nounReally 'steps': a run of steps, especially ones climbing a slope, and it can also mean a terrace. For the staircase of a building it is seldom the word you want — use 階段.

階段 is the word you want for a staircase or flight of stairs; 「だんだん」 really means steps — a run of steps or a terrace — and is only a marginal match for 'staircase'.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 階段かいだんstairs
• 上がり段あがりだんstaircase
• 梯子段はしごだんstep
• 階段室かいだんしつstairwell
• だんだんsteps