I've always loved poking at wordy confusions, and the jealous/envious pair is one of my favorites because they feel similar but live in different rooms of your emotional house.
In plain terms, envy is about wanting what someone else has — their job, their car, their knack for drawing — you look at another person's possession or trait and feel a lack. Jealousy usually involves three people or a triad: it's the fear of losing something you already have (attention, affection, status) to someone else. So if my colleague gets promoted and I wish I had that role, that's envy. If my friend starts hanging out with someone else and I worry they'll stop being close to me, that's jealousy. The tone matters too: envy often burns with longing or admiration (sometimes resentful), while jealousy mixes fear, suspicion, and protective behavior.
I think of 'Othello' when I see jealousy spun into something dangerous — it's darker, prone to insecurity-fueled actions. Envy can be oddly motivating (I want what they have and maybe I'll work for it), while jealousy tends to push people into defense or control. Both are normal; noticing which one I'm feeling helps me decide whether to act, reflect, or let it go.