1. a person who is between 90 and 99 years old

1. being between 90 and 99 years old

Examples

• The nonagenarian celebrated her 95th birthday with her great-grandchildren.
• At 92, he was the oldest nonagenarian in the retirement community.
• The nonagenarian author published her final novel at age 94.
• She remained active and sharp-minded as a nonagenarian.
• The nonagenarian couple had been married for 70 years.
• His nonagenarian grandmother still lived independently in her own home.