1 : octogenarian. 2 : based on the number 80.

What is an eighty year old called?

English Language Learners Definition of octogenarian

: a person who is between 80 and 89 years old. See the full definition for octogenarian in the English Language Learners Dictionary. octogenarian.

What do you call a person who is 50 years old?

A quinquagenarian is someone in their 50s (50 to 59 years old), or someone who is 50 years old. Quinquagenarian can also be used as an adjective to describe someone in their 50s, as in I have entered my quinquagenarian years.