SEPTUAGENARIAN
septuagenarian
(noun) someone whose age is in the seventies
Source: WordNet® 3.1
Etymology
Adjective
septuagenarian (not comparable)
Being between the age of 70 and 79, inclusive. In one's eighth decade.
Of or relating to a septuagenarian.
Noun
septuagenarian (plural septuagenarians)
One who is between the age of 70 and 79, inclusive.
Coordinate terms
• vicenarian
• tricenarian
• quadragenarian
• quinquagenarian
• sexagenarian
• octogenarian
• nonagenarian
• centenarian
Source: Wiktionary
Sep`tu*a*ge*na"ri*an, n.
Definition: A person who is seventy years of age; a septuagenary.
Source: Webster’s Unabridged Dictionary 1913 Edition