13-Letter Words Matching __N________M_

There are 12 13-letter words that match __N________M_. 3 are common words, such as CONSERVATISMS and GENERALISSIMO. A rarer one is SYNDACTYLISMS. In this set, S is the most frequent open letter (11 words). 6 words contain a doubled letter.

Full list 12

conservatismsgeneralissimotonsillectomypancreatotomyunnilpentiumsunnilquadiumsconnubialismsmonomorphismsmonorchidismsnonclassroomsnonpetroleumssyndactylisms

About this list

Words
12 (3 common words)
Common example
conservatisms
Rare example
syndactylisms
Doubled letters
6
Ending in S
9
Most frequent letter
S (11)

Questions

How many 13-letter words matching __n________m_ are there?

12. 3 of them are common words.

What is a common example?

CONSERVATISMS is among the common words in this set.