13-Letter Words Matching ____R____O___

There are 46 13-letter words that match ____R____O___. 12 are common words, such as BIDIRECTIONAL and CLEARINGHOUSE. A rarer one is SUPERREGIONAL. In this set, I is the most frequent open letter (37 words). 11 words contain a doubled letter.

Full list 46

Common words

bidirectionalclearinghousecongressionalcongresswomancongresswomenhyperthyroidsinformationalinstructionalinternationalinterpersonalobservationalunderemployed
bidirectionalclearinghousecongressionalcongresswomancongresswomenhyperthyroidsinformationalinstructionalinternationalinterpersonalobservationalunderemployedanthropologicanthroposophyaspergillosesaspergillosisastereognosiscompressionalhypermetropiainscriptionalprocreationalquadrillionthreformationalrepartitionedsupernationalabstractionalanthropomorphcontractionaldeformationalfluorochromesheterozygosesheterozygosisheterozygoteshyperhidroseshyperhidrosishypermetropichyperrationalinteractionalinterneuronalinterregionalpolyribosomalpolyribosomesprogressionalsuperdiplomatsuperpersonalsuperregional

About this list

Words
46 (12 common words)
Common example
bidirectional
Rare example
superregional
Doubled letters
11
Ending in S
11
Most frequent letter
I (37)

Questions

How many 13-letter words matching ____r____o___ are there?

46. 12 of them are common words.

What is a common example?

BIDIRECTIONAL is among the common words in this set.