9-Letter Words Matching ____M__M_

There are 12 9-letter words that match ____M__M_. 4 are common words, such as CHROMIUMS and DYNAMISMS. A rarer one is SEISMISMS. In this set, I is the most frequent open letter (12 words). 0 words contain a doubled letter.

Full list 12

chromiumsdynamismsencomiumsoptimismsalarmismsendemismstotemismsdidymiumsdreamtimeopiumismsracemismsseismisms

About this list

Words
12 (4 common words)
Common example
chromiums
Rare example
seismisms
Doubled letters
0
Ending in S
11
Most frequent letter
I (12)

Questions

How many 9-letter words matching ____m__m_ are there?

12. 4 of them are common words.

What is a common example?

CHROMIUMS is among the common words in this set.