Primary, secondary, tertiary...

I have wondered what comes next for a looong time and simply forgot to Google it. But the other day I remembered when I was at the computer, so I give you the AskOxford answer:

The sequence continues with quaternary, quinary, senary, septenary, octonary, nonary, denary. Words also exist for `twelfth order' (duodenary) and `twentieth order' (vigenary).

For what it's worth, I figured the next word was 'quaternary' or 'quarternary'.