In University Chemistry, we always talked about primary carbons and secondary carbons and tertiary carbons. Then there were quaternary carbons, that I'd never heard of. I always wondered what came after quartenary? So, I looked it up and found this:
What comes after primary, secondary, tertiary?
The sequence continues with quaternary, quinary, senary, septenary, octonary, nonary, denary. Words also exist for `twelfth order' (duodenary) and `twentieth order' (vigenary).
Quinary and senary? Good to know. I think I'll start using that.