octogenarian

名词 octogenarian:

1. someone whose age is in the eighties

形容词 octogenarian:

1. being from 80 to 89 years old

1. She is very active for an octogenarian.
   她已经是八旬老人了，还很精神。

oc.to.ge.nar.i.an

adj.（形容词）
Being between 80 and 90 years of age.
在80到90岁之间的
n.（名词）
A person between 80 and 90 years of age.
在80到90岁之间的人

来源：
From French octogénaire
源自 法语 octogénaire
from Latin octôgôn3rius [containing eighty]
源自 拉丁语 octôgôn3rius [含有八十的]
from octôgôno [eighty each]
源自 octôgôno [每一个八十]
from octôgint3 [eighty]
源自 octôgint3 [八十]
octô [eight] * see oktô(u)
octô [八] *参见 oktô(u)
-gint3 [ten times] * see dekô
-gint3 [十次] *参见 dekô