13-Letter Words Matching _____A___O___

There are 18 13-letter words that match _____A___O___. 2 are common words, such as BURGLARPROOFS and PHARMACOPOEIA. A rarer one is ZOOPLANKTONIC. In this set, I is the most frequent open letter (15 words). 4 words contain a doubled letter.

Full list 18

burglarproofspharmacopoeiapharmacologicspermatozoidstransactionalunimpassionedabstractionalcontractionalcytotaxonomicinteractionalneuroanatomicnonclassroomsovercautionedrarefactionalspermatogoniaspermatozoanswitenagemoteszooplanktonic

About this list

Words
18 (2 common words)
Common example
burglarproofs
Rare example
zooplanktonic
Doubled letters
4
Ending in S
5
Most frequent letter
I (15)

Questions

How many 13-letter words matching _____a___o___ are there?

18. 2 of them are common words.

What is a common example?

BURGLARPROOFS is among the common words in this set.