In modern English usage, the difference
between jealousy and envy is not clear-cut, as this Merriam-Webster article helpfully points out. In fact, the two terms have become so muddled that three
major language guides from the mid-20th century disagree about their respective
meanings.
For convenience and to avoid making the
confusion worse, I’ll use “jealous” to describe the anticipative emotions
that arise over losing something you have, and “envious” to describe the desire
to possess what belongs to someone else.
But I won’t pretend to have the final word
on the subject.