Nonagenarian
/ˌnəʊnədʒəˈneriən,ˌnɑːnədʒəˈneriən/
Definition 1 of 1
Pro Tip 1/3Age Bracket
Refers specifically to people in their 90s. Using it for someone 89 or 100 is incorrect. 
After his 90th birthday, Uncle Joe became a proud nonagenarian.
Pro Tip 2/3Context Specific
Best used in contexts related to age, such as health, life achievements, or generational discussions. 
The nonagenarian shared stories from WWII, captivating the younger audience.
Pro Tip 3/3Respectful Tone
Carries a tone of respect or admiration for reaching a very advanced age. 
The nonagenarian was honored for her decades of community service.