The term nonagenarian refers to a person who is 90 years old. Technically, nonagenarian refers to an individual who is between 90 and 99 years old.
The term nonagenarian is believed to have originated in the early 19th century. It came from the Latin word nonagenarius. Nonagenarian can be used as either a noun or an adjective. Prior to turning 90 years old, people are known as octogenarians, or those who live to be 80 years old. More people than ever are living to reach the nonagenarian plateau. In 1980, the U.S. Census Bureau found that there were approximately 720,000 nonagenarians in the country. In 2010, this number increased to 1.9 million nonagenarians.