15-Letter Words Matching __________O___M

There are 13 15-letter words that match __________O___M. 2 are common words, such as CONSERVATIONISM and INTERVENTIONISM. A rarer one is THERMOPERIODISM. In this set, I is the most frequent open letter (13 words). 2 words contain a doubled letter.

Full list 13

conservationisminterventionismnitrochloroformpresentationismpreservationismresurrectionismsuperpatriotismthromboembolismassimilationismhypercatabolismhypermetabolismphonocardiogramthermoperiodism

About this list

Words
13 (2 common words)
Common example
conservationism
Rare example
thermoperiodism
Doubled letters
2
Ending in S
0
Most frequent letter
I (13)

Questions

How many 15-letter words matching __________o___m are there?

13. 2 of them are common words.

What is a common example?

CONSERVATIONISM is among the common words in this set.