What does the facial expression of having one eyebrow raised mean?

It seems to mean different things, but it's not very clear how to put them into words.





One is Spock from Star Trek, who often made this expression while frowning.


There is Dwayne ';The Rock'; Johnson who's trademark was this, but smiling.


And one that comes to mind is the emoticon O.oWhat does the facial expression of having one eyebrow raised mean?
It means, 'Really?'.What does the facial expression of having one eyebrow raised mean?
I view it as WOW, Oh really? Whaat? Huh? and Straight?
quizzical
curiosity, befuddlement, surprise...

make up