13-Letter Words Matching A__A_________

There are 13 13-letter words that match A__A_________. 5 are common words, such as AMBASSADORIAL and ASSASSINATING. A rarer one is ASSASSINATORS. In this set, I is the most frequent open letter (12 words). 8 words contain a doubled letter.

Full list 13

ambassadorialassassinatingassassinationattainabilityaudaciousnessadiabaticallyadiathermancyamiablenessesaquaculturistagranulocytesalkalimetriesarmamentariumassassinators

About this list

Words
13 (5 common words)
Common example
ambassadorial
Rare example
assassinators
Doubled letters
8
Ending in S
5
Most frequent letter
I (12)

Questions

How many 13-letter words matching a__a_________ are there?

13. 5 of them are common words.

What is a common example?

AMBASSADORIAL is among the common words in this set.