The term "middle age" refers to a period in between young adulthood and old age. It is generally used to describe individuals who are beyond their childhood years, but have not yet reached retirement age or senior citizenship. The specific age range that falls under the category of middle age can vary depending on cultural perspectives and individual circumstances, but it typically includes people in their 30s, 40s, and 50s. During this time, individuals are often focused on building careers, raising families, and establishing financial stability.