Is vigenary a real word?

Question

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, here and here 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?

Answer 1

Vigenary is marked by the OED as rare, but the alternative vicenary is not so marked.

Vicenary ... adj. ‘Belonging to twenty’ (Bailey, 1727); based on the number twenty. Cf. vigenary adj.

• a1831 G. Peacock Arithm. in Encycl. Metrop. (1845) I. 371/1 Such a practice would naturally lead to the formation of a vicenary scale of numeration.
• 1834 Penny Cycl. II. 337/2 In France the scale from 60 to 100 is strictly vicenary (by twenties).

The root of both 'vigenary' and 'vicenary' is from Latin vīcēnārius, in turn from vīcēnī, the distributive form of vīgintī ('twenty').

Answer 2

Probably not. Vigesimal is a word, but the series primary, secondary, tertiary… seems to cover only numbers from 1 to 10 and 12:

https://en.oxforddictionaries.com/explore/what-comes-after-primary-secondary-tertiary