Octogenarius

Part of speech: noun, adjective

Definitions

1. A person who is between eighty and eighty-nine years old
2. An individual belonging to the age group of eighty to eighty-nine years
3. Referring to someone in their eighth decade of life

Etymology: "Octogenarius" is Latin for "of eighty," built from "octogeni," meaning "eighty each" (distributive numeral), itself from "octoginta," eighty. The suffix "-arius" forms adjectives and nouns meaning "pertaining to" or "a person belonging to," so the word literally describes someone of the eighty-year bracket. English took it over as a learned borrowing, which is why it looks more Latin than most everyday words. Its use is tied to the ancient Roman idea of age categories: classical Latin writers divided life into decades, and the eighty-to-eighty-nine group needed its own label. The Latin noun "octogenarius" was used in this sense, and English adopted the term for the same purpose, giving the decade-based age bands their precise names.

Synonyms: octogenarian, eighty-year-old