15-Letter Words Matching ____R_________M

There are 20 15-letter words that match ____R_________M. 2 are common words, such as HYPERTHYROIDISM and INTERVENTIONISM. A rarer one is SUPERPARASITISM. In this set, I is the most frequent open letter (20 words). 1 words contain a doubled letter.

Full list 20

hyperthyroidisminterventionismdepartmentalismexperientialismexperimentalisminstrumentalismmajoritarianismresurrectionismsupernaturalismsuperpatriotismanthropopathismantirationalismantiromanticismenterobacteriumgovernmentalismhypercatabolismhyperinsulinismhypermetabolismhyperparasitismsuperparasitism

About this list

Words
20 (2 common words)
Common example
hyperthyroidism
Rare example
superparasitism
Doubled letters
1
Ending in S
0
Most frequent letter
I (20)

Questions

How many 15-letter words matching ____r_________m are there?

20. 2 of them are common words.

What is a common example?

HYPERTHYROIDISM is among the common words in this set.