These definitions of jealousy share two basic themes. First, all the definitions imply a triad composed of a jealous individual, a partner, and a perception of a third party or rival. Second, all the definitions describe jealousy as a reaction to a perceived threat to the relationship between two people, or a dyad. Jealous reactions typically involve aversive emotions and/or behaviors that are assumed to be protective for their attachment relationships. These themes form the essential meaning of jealousy in most scientific studies.