kaidan agaridan

[pacerier]

what's the difference between kaidan and agaridan?

 

[Emoni]

上がり段 階段

My GUESS is that an Agaridan are the actual "steps" and that Kaidan refers to the staircase itself.

Hopefully someone much more knowledgeable can help you out, but I wanted to give my input in case your post is missed. I'm just as curious.

 

[nice gaijin]

agaridan seems more like the steps leading up to something (あがる is used for entering like a residence), and kaidan is more general, but if you look at the kanji, it would mean the stairs leading from one storey to the next if you took them literally.

 

[stymo]

I agree with you two. If I hear the word "agari-dan", what comes up first to my mind is the step of the front door (shikidai), which is well seen at the typical Japanese style house.
Here is an image of agaridan (Remove the spaces):

Hope it helps