osÂ·teÂ·opÂ·aÂ·thy. n. 1. A system of medicine practiced by licensed osteopathic physicians that involves palpation and noninvasive manipulation of the musculoskeletal system in the diagnosis and treatment of physical dysfunction, in conjunction with other medical, surgical, pharmacological, and therapeutic procedures.
Average Age of Presidents. The majority of the presidents were between the ages of 50 and 59 when they were elected into office. The youngest elected president was John F. Kennedy at age 43. The oldest elected president was Ronald Reagan at age 69.
Barack Obama, age 47 when he took office, is one of the youngest presidents. Just Ulysses S. Grant (46), Bill Clinton (46), John F. Kennedy (43) and Theodore Roosevelt (42) were younger. Roosevelt was 42 years, 322 days old when he became president after the death of William McKinley in 1901.