The French military term meant to withdraw, as from a battle, not from a lifetime of work.
Retire entered English in the 1530s from the French retirer, meaning to draw back or withdraw.1 The earliest uses were military: to retire meant to pull troops away from the front. The word carried connotations of strategic retreat, not rest.
The sense of withdrawing from active working life appeared gradually in the seventeenth and eighteenth centuries, but the modern concept of retirement, a defined stage of life supported by pension income, did not exist until the late nineteenth century.
Otto von Bismarck's introduction of the Old Age and Disability Insurance Bill in 1889 created the first government-sponsored retirement age, initially set at seventy, for the German Empire.2 Before this, most people worked until they were physically unable to continue. The idea that a government would define a specific age at which a person should stop working was new.
The American Social Security Act of 1935 set sixty-five as the age of eligibility for old-age benefits, influenced partly by the German model and partly by actuarial calculations about life expectancy and labor force participation.3
The word that began as a military maneuver and became an economic category now describes a cultural aspiration. In Japanese, teinen (定年) means fixed year, referring to the mandatory retirement age. The French original, with its sense of withdrawing from a field of engagement, remains embedded in the English word, even as the field in question has shifted from the battlefield to the office.