Adulthood/ˈædʌlthʊd/ Definition 1 of 2Pro Tip 1/3Life Stages Adulthood is a period that follows childhood and adolescence. She faced many challenges during her transition from adolescence to adulthood. Pro Tip 2/3Personal Growth Adulthood often involves increased responsibilities and independence. Adulthood brought new freedoms in his personal and professional life. Pro Tip 3/3Cultural Variation The age defining adulthood can vary in different cultures. In some cultures, adulthood is celebrated with coming-of-age ceremonies.