11-Letter Words Matching ____A__C___

There are 20 11-letter words that match ____A__C___. 5 are common words, such as CAPTAINCIES and PICKABACKED. A rarer one is VULCANICITY. In this set, I is the most frequent open letter (17 words). 4 words contain a doubled letter.

Full list 20

captainciespickabackedprevaricatesabbaticalssyllabicateacatalecticaromaticitymechanicianpentadactylsyllabicitybidialectalcyclazocinegentamicinsmechanicalspentazocineultrafichesultrasecretultravacuumvolcanicityvulcanicity

About this list

Words
20 (5 common words)
Common example
captaincies
Rare example
vulcanicity
Doubled letters
4
Ending in S
5
Most frequent letter
I (17)

Questions

How many 11-letter words matching ____a__c___ are there?

20. 5 of them are common words.

What is a common example?

CAPTAINCIES is among the common words in this set.