The word "jealousy" is often used as if it were synonymous with envy; but I think the distinction worth preserving. Jealousy is predominantly concerned with the fear of loss of something one possesses, envy with the wish to own something another possesses. Othello suffers from the fear that he has lost Desdemona's love. Iago suffers from envy of the position held by Cassio, to which he feels entitled.