15-Letter Words Matching ____R_____O____

There are 19 15-letter words that match ____R_____O____. 7 are common words, such as HETEROGENEOUSLY and INSURRECTIONIST. A rarer one is NONPROFESSORIAL. In this set, E is the most frequent open letter (18 words). 7 words contain a doubled letter.

Full list 19

heterogeneouslyinsurrectionistinterrogatoriesinterventionisminterventionistsuperstitiouslyunceremoniouslycontradictorilyinsurrectionaryinterrogatorilyresurrectionismresurrectionistsuperheterodynesuperpatriotismcontradictorieshypercatabolismhypermetabolisminternucleotidenonprofessorial

About this list

Words
19 (7 common words)
Common example
heterogeneously
Rare example
nonprofessorial
Doubled letters
7
Ending in S
2
Most frequent letter
E (18)

Questions

How many 15-letter words matching ____r_____o____ are there?

19. 7 of them are common words.

What is a common example?

HETEROGENEOUSLY is among the common words in this set.