octogenary
adjective
oc·tog·e·nary
(ˈ)äk¦täjəˌnerē
1
: octogenarian
2
: based on the number 80
Word History
Etymology
Latin octogenarius containing or consisting of eighty, from octogeni eighty each (from octoginta eighty, from octo eight + -ginta —akin to Latin -ginti in viginti twenty) + -arius -ary