What is the word in Spanish meaning mean?

I depends on context. As in "unkind", it is "malo or antipático". If you want to say "nasty", use "malhumorado". There are various other less common usages.

As a verb, "to mean" is "significar/querer decir"

That Word means "elephant". = Esa palabra significa «elefante».

There are two. I mean, three. = Son dos. Quiero decir, tres.