Wisdom has been discussed for centuries in religious and philosophical texts. It is often viewed as a fuzzy psychological construct analogous to consciousness, stress, and resilience. This essay provides an understanding of wisdom as a scientific construct, based on empirical research starting in the 1970s. The focus is on practical rather than theoretical wisdom. While there are different conceptualizations of wisdom, it is best defined as a complex human characteristic or trait with specific components: social decision-making, emotional regulation, prosocial behavior (such as empathy and compassion), self-reflection, acceptance of uncertainty, decisiveness, and spirituality. These psychological processes involve the fronto-limbic circuitry. Wisdom is associated with positive life outcomes including better health, well-being, happiness, life satisfaction, and resilience. Wisdom tends to increase with active aging, facilitating a contribution of wise grandparents to promoting fitness of younger kin. Despite the loss of their own fertility and physical health, older adults help enhance their children's and grandchildren's well-being, health, longevity, and fertility-the "grandmother hypothesis" of wisdom. Wisdom has important implications at individual and societal levels and is a major contributor to human thriving. We need to place a greater emphasis on promoting wisdom through our educational systems from elementary to professional schools.