> Do you think the word "rational" in rational actor, rational investor and rational market, has exactly the same meaning?

Rational actor and rational investor, the same. Rational market, different. But I only know the term "rational market" through its use in the fixed expression "the market can stay irrational longer than you can stay solvent".

> Do you think as people commonly understand these terms (I don't mean economists) the answer would be the same?

I guess I can't really speak to this.