I've noticed my American DiL uses jealous when I would probably use envious, and often when she doesn't really mean it.
For example, if I put a photo on Facebook of me on a tropical beach, she'll put something like 'Jealous!!' followed by j/k which means joking. She certainly doesn't mean that she's eaten up with kept-awake-at-night-type jealousy.
I think your definition's neat Elegran, but not sure I agree with it....for example, a sibling could be jealous because they thought another sibling was treated by the parents more favourably, but in that situation they aren't fearful of something being taken away, they are upset because they perceive someone has something they have never had.
I would suggest a more clinical take on it.
To me, feelings of envy come within the normal spectrum of emotions, whereas jealousy can develop into something pathological.