I didn't discovered the word "legendary", because are discussing about the definition. My dictionary gives that definition and yes, I can find myself in that explanation.
And unique, there is much more then Pokemon types. I said: Every legend has it's own reason.
Rare and unique is different. Rare, maybe there are more? Or maybe not? Unique, there is only one.
And that's what I mean with the number. If there alot of the same, it isn't legend, it's just like others then: normal.