[ok-tuh-juh-nair-ee-uh n]

adjective Also oc·tog·e·nar·y [ok-toj-uh-ner-ee] /ɒkˈtɒdʒ əˌnɛr i/.

of the age of 80 years.
between 80 and 90 years old.


a person who is between 80 and 90 years old.

Nearby words

  1. octobrist,
  2. octocentenary,
  3. octodecillion,
  4. octodecimo,
  5. octofoil,
  6. octomerous,
  7. octometer,
  8. octonary,
  9. octopod,
  10. octopus

Origin of octogenarian

1805–15; < Latin octōgēnāri(us) comprising eighty, eighty years old (equivalent to octōgēn(ī) eighty each + -ārius -ary) + -an

Related formsoc·to·ge·nar·i·an·ism, noun

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for octogenarian

British Dictionary definitions for octogenarian


less commonly octogenary (ɒkˈtɒdʒɪnərɪ)

noun plural -narians or -naries

a person who is from 80 to 89 years old


of or relating to an octogenarian

Word Origin for octogenarian

C19: from Latin octōgēnārius containing eighty, from octōgēnī eighty each

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for octogenarian



1789, with -an + French octogénaire "aged 80," from Latin octogenarius "containing eighty," from octogeni "eighty each," related to octoginta "eighty," from octo "eight" (see eight) + -genaria "ten times," from PIE *dkm-ta-, from *dekm- "ten" (see ten). As an adjective from 1784.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for octogenarian




Being between 80 and 90 years of age.


A person between 80 and 90 years of age.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.