I don't know the answer. i only wish i had thought to ask this question, myself. hope to read an answer.

it really doesnt matter, i guess its a difference between indoors and outdoors, but i think people are just used to the inside as stairs and outside as steps.. like porch steps and so on and so fourth...

Where I'm from we call it stairs no matter where we are. Indoor or out.

What you've got to remember is that there is a difference between English English and American English. In Britain there is no difference.

I always understood "steps" to mean the type that are not completely finished (the vertical space between each step is open) and "stairs" to mean the type that have that space closed. This is just the usage in my family.

good question...i have no clue!

Stair or stairs is short for "stairway."

I'm going with the above answer, sort of- "stairs" is indeed short for stairway, but it can also be short for "staircase." I always thought anything with a "case" built around it- primarily this would be banisters and such- should be stairs, and that steps are simply open flat descent. Usually this seems to fit into the indoor/outdoor pattern you note. I think it is also possible the relative rise vs depth may affect the correct nomenclature.

I know this doesn't really make much sense, but this is how I've always thought of it. I'm HORRIBLE at explaining things, so if anyone can find a better way to put this, feel free: Usually when people say "steps" they are referring to a staircase which is only a few steps high, and calling them "stairs" would be over-glorifying them. Generally these small staircases are found outside. Usually as an entrance to a building. Hence "steps outside." Large staircases are usually found inside, hence "stairs inside." If you lived in an apartment building, and the staircase to the second floor was outside, do you call it steps, or stairs? I've always heard it called stairs. But that's just me. My house is one-story, but my room is a little lower down then the rest of the house, so there are two steps at the entrance to my room, and we call them "steps." Again, that's just me. I THINK what I'm trying to say is, we only usually here the small staircases called steps, and there usually outside, so we assume all staircases outside are called "steps." And vice-versa. I don't know if this helped or not. I hope it clears things up a little.

I've always thought of stairs or stairways to gain a level or floor(like a house or parking garage) and steps to gain an entrance or lead up to one (like the back door or even porch to your house or school) or a passage or to gain passage (through a garden or park)

I'm sure I'm just restating the above but... "Steps" implies just a few...ledges? (I don't know what to call them individually.) Usually, only two or three together. It doesn't matter if it's inside or outside, but more often there are a couple steps leading up the the doors. "Stairs" typically implies many steps, like more than 8 or 9. I wouldn't call the steps in a split-level "stairs," you know?

I didn't know they were...if anything I'd think it has to do with how many there are - if it's a dozen or so stairs, inside or out, they're stairs. But if it's only 1-2, they're steps, inside or out.