13-Letter Words Matching _A________A__

There are 13 13-letter words that match _A________A__. 7 are common words, such as BACCALAUREATE and BACCHANALIANS. A rarer one is GALACTOSIDASE. In this set, I is the most frequent open letter (12 words). 3 words contain a doubled letter.

Full list 13

baccalaureatebacchanalianscaravanseraisparliamentaryparticleboardsalutatoriansvaudevilliansbacteriophagebacteriostatsmajoritariansradioactivatebacteriophagygalactosidase

About this list

Words
13 (7 common words)
Common example
baccalaureate
Rare example
galactosidase
Doubled letters
3
Ending in S
6
Most frequent letter
I (12)

Questions

How many 13-letter words matching _a________a__ are there?

13. 7 of them are common words.

What is a common example?

BACCALAUREATE is among the common words in this set.