15-Letter Words Matching ______I_____N__

There are 19 15-letter words that match ______I_____N__. 4 are common words, such as GEOENGINEERINGS and IMPROVISATIONAL. A rarer one is TRANSPIRATIONAL. In this set, O is the most frequent open letter (18 words). 8 words contain a doubled letter.

Full list 19

geoengineeringsimprovisationalmountaineeringsphotofinishingsbioengineeringsbioluminescencecommunicationalhallucinationalarrondissementsbenzodiazepinesdivertissementsinterdivisionalinvestigationalmultidivisionalnonachievementsnonengineeringsparticipationalrecombinationaltranspirational

About this list

Words
19 (4 common words)
Common example
geoengineerings
Rare example
transpirational
Doubled letters
8
Ending in S
9
Most frequent letter
O (18)

Questions

How many 15-letter words matching ______i_____n__ are there?

19. 4 of them are common words.

What is a common example?

GEOENGINEERINGS is among the common words in this set.