Compatibility refers to how well two people's traits, energies, or charts are believed to align in a relationship, whether romantic, platonic, or professional. It's often assessed astrologically by comparing sun signs or full birth charts, but the term is used more broadly in psychic and relationship readings to describe the overall harmony, or friction, between two people's personalities and needs.

High compatibility doesn't guarantee an easy relationship, and lower compatibility doesn't rule one out. Most readers treat it as one piece of a much larger picture rather than the deciding factor.