Translation guide
In Japanese, the word for 'stair' depends on whether you mean a single step, a flight of stairs, or stairs as a structure. The most common word is 階段 (kaidan), which refers to stairs as a whole. For a single step, use 段 (dan).
Referring to a set of steps that connect two levels, such as in a building or outdoors.
The standard word for stairs or a staircase. Use this in most situations.
Please go up the stairs.
These stairs are steep, aren't they?
Can also be used with counters to specify flights of stairs.
Go up one flight of stairs, and it's on the right.
Referring to one individual step in a staircase.
Describing types of stairs or stair-related objects.
Used in compounds to specify types of stairs.
The emergency stairs are over there.
Also used in compounds for step-like things.
階段 (kaidan) refers to the whole staircase, while 段 (dan) refers to a single step. Using 階段 when you mean a single step can cause confusion.
This staircase has 10 steps.
Use the counter 段 (だん) to count steps: 一段 (いちだん), 二段 (にだん), etc. For flights of stairs, you can use 一階段 (ひとかいだん), but it's less common; usually you just say 階段を上る/下りる (go up/down the stairs).
Adjust the height of the steps.
This spiral staircase is beautiful, isn't it?
ここに段差があるので気をつけてください。
There's a step here, so please be careful.