13-Letter Words Matching _R_________M_

There are 12 13-letter words that match _R_________M_. 3 are common words, such as PRASEODYMIUMS and PROTACTINIUMS. A rarer one is TRIUMPHALISMS. In this set, S is the most frequent open letter (12 words). 1 words contain a doubled letter.

Full list 12

praseodymiumsprotactiniumstransvestismsprostatectomybronchospasmscryptorchismsergastoplasmsfraternalismsgreenbackismspragmaticismstrimethoprimstriumphalisms

About this list

Words
12 (3 common words)
Common example
praseodymiums
Rare example
triumphalisms
Doubled letters
1
Ending in S
11
Most frequent letter
S (12)

Questions

How many 13-letter words matching _r_________m_ are there?

12. 3 of them are common words.

What is a common example?

PRASEODYMIUMS is among the common words in this set.