13-Letter Words Matching ______R_____M

There are 18 13-letter words that match ______R_____M. 4 are common words, such as EQUESTRIANISM and INDUSTRIALISM. A rarer one is SUPERORGANISM. In this set, S is the most frequent open letter (17 words). 5 words contain a doubled letter.

Full list 18

equestrianismindustrialismmicroorganismvegetarianismantiterrorismcatastrophismcontrarianismfruitarianismimmaterialismindeterminismpedestrianismzoosporangiumblepharospasmcounterreformcounterstreamhyperurbanismpococurantismsuperorganism

About this list

Words
18 (4 common words)
Common example
equestrianism
Rare example
superorganism
Doubled letters
5
Ending in S
0
Most frequent letter
S (17)

Questions

How many 13-letter words matching ______r_____m are there?

18. 4 of them are common words.

What is a common example?

EQUESTRIANISM is among the common words in this set.