oc ‧ to ‧ ge ‧ nar ‧ i ‧ an /ˌɒktəʊdʒəˈne ə riən, ˌɒktəʊdʒɪˈne ə riən, -tə- $ ˌɑːktoʊ-/ BrE AmE noun [countable]
[ Date: 1800-1900 ; Language: Latin ; Origin: octogenarius 'containing eighty' , from octoginta 'eighty' ]
someone who is between 80 and 89 years old