There are no perfect rhymes for octogenarian, but these words all end with -arian and could be used in poetry: 1. abecedarian 2. actiniarian 3. adessenarian 4. agrarian 5. alphabetarian 6....
80, because the word -octo- is in it and words with -octo- or something like that in it would most likely have something to do with 8. Like these words:octopus- 8 legsocho- 8 in Spanishoctave- move 8...