octantal - Octantal is 18, like a double nonary, a triple sextant, and

Octantal is 18, like a double nonary, a triple sextant, and the number that makes you legally allowed to mess up your life.

My lawyer said I'm octantal now. I'm still waiting for my freedom.

I turned octantal and suddenly my mom stopped calling me a baby.

The DM said, 'You're octantal? Finally, I can stop being the baby of the group.'