15-Letter Words Matching ____A_A________

There are 15 15-letter words that match ____A_A________. 4 are common words, such as COMPARABILITIES and HAPHAZARDNESSES. A rarer one is UPGRADABILITIES. In this set, S is the most frequent open letter (14 words). 5 words contain a doubled letter.

Full list 15

comparabilitieshaphazardnessesimplacabilitieslackadaisicallydisparatenessesappealabilitiescomparativenessecocatastrophesglutaraldehydesintravascularlyrepeatabilitiesspreadabilitiesultrafastidiousultramarathonerupgradabilities

About this list

Words
15 (4 common words)
Common example
comparabilities
Rare example
upgradabilities
Doubled letters
5
Ending in S
12
Most frequent letter
S (14)

Questions

How many 15-letter words matching ____a_a________ are there?

15. 4 of them are common words.

What is a common example?

COMPARABILITIES is among the common words in this set.