A relationship or an affinity between people or things in which whatever affects one correspondingly affects the other. Mutual understanding or affection arising from this relationship or affinity. The act or power of sharing the feelings of another. A feeling or an expression of pity or sorrow for the distress of another; compassion or commiseration. Often used in the plural. See Synonyms at pity. Harmonious agreement; accord: He is in sympathy with their beliefs. A feeling of loyalty; allegiance. Often used in the plural: His sympathies lie with his family. Physiology A relation between parts or organs by which a disease or disorder in one induces an effect in the other.