I was interested in determining words to describe ordinal *Latinate* series numbering above orders of 10 (i.e., "denary"). 

I found "duodenary", which makes sense based on the latin root *duodecim*, meaning 'twelve.' (see also etymology of the duodenum of the small intestine -- *duodeni*, meaning 'in twelves.').

However, I found no evidence of other ordinal numbering adjectives other than that for 20.

I have two questions:

1. [Here](http://www.english-for-students.com/Primary-1.html), [here](http://international-dictionary.com/definitions/?english_word=vigenary) and [here](https://en.wiktionary.org/wiki/vigenary) suggest that "**vigenary**" is the Latinate ordinal term for "twentieth" (or "of the twentieth order"). However, none of these sources come across as legitimate. Can anyone confirm for me (through a more trustworthy and proper source) that "vigenary" is in fact the proper word to use here?
2. Do other Latinate ordinal adjectives (for orders > 10) exist?