15-Letter Words Matching ____R____O_____

There are 31 15-letter words that match ____R____O_____. 9 are common words, such as ANTHROPOLOGICAL and ANTHROPOLOGISTS. A rarer one is UNCHRONOLOGICAL. In this set, I is the most frequent open letter (27 words). 7 words contain a doubled letter.

Full list 31

Common words

anthropologicalanthropologistsanthropomorphicbidirectionallyhyperthyroidisminternationallyobstructionismsobstructionistsunderemploymentabstractionismsabstractionistscongressionally
anthropologicalanthropologistsanthropomorphicbidirectionallyhyperthyroidisminternationallyobstructionismsobstructionistsunderemploymentabstractionismsabstractionistscongressionallydistributorshipheterochromaticheterochromatininterpersonallylabyrinthodontsobservationallyanthroposophiesdestructionistsexoerythrocytichyperresponsivehypersomnolenceinformationallyliturgiologistsrechromatographreservationistsrestrictionismsrestrictionistssuperphenomenonunchronological

About this list

Words
31 (9 common words)
Common example
anthropological
Rare example
unchronological
Doubled letters
7
Ending in S
12
Most frequent letter
I (27)

Questions

How many 15-letter words matching ____r____o_____ are there?

31. 9 of them are common words.

What is a common example?

ANTHROPOLOGICAL is among the common words in this set.