I can't see how many letters the word has. Can youremind us? >> Sure! 8 letters. Only two vowels (not "e"). Actually, the same vowel repeated twice.
Does it have doors? Windows? >> There are lots of doors in it. And lots of windows, too.
It is intended that you go inside of it? >> I'd say yes, especially when you think of it as an adverb, but I'm not sure you would use "inside" with this word ...
Is it taller than 6 meters (about 20 feet)?
>> With reference to ground level, you mean? If yes: some parts are much higher than that. Some are lower. Smaller than a typical house?
>> Much, much bigger.Ok, I'll drop a hint: according to my (British) dictionary, it's "especially NAmE".