octogenary UK /ɒkˈtɒd͡ʒ.ɪ.nə.ri/US /ɑkˈtɑ.d͡ʒəˌnɛr.i/adjective 2noun 1forms 1 adjective2 •(no longer used) Of or related to the number 80. •(no longer used) Synonym of octogenarian: lasting or aged 80 years; 80-year-old.[…] he went to visit him, being then octogenary, and very decrepid with the gowt, but had his sight and understanding. — 1697 noun1 •(no longer used) Synonym of eightysomething: a person 80 to 89 years old. formsoctogenaries
