9-Letter Words Matching ____S___M

There are 26 9-letter words that match ____S___M. 16 are common words, such as ANTISERUM and BARNSTORM. A rarer one is VASOSPASM. In this set, O is the most frequent open letter (19 words). 8 words contain a doubled letter.

Full list 26

Common words

antiserumbarnstormclassroomcolostrumcrossbeamdisesteemfetishismfirestormhailstormmaelstrompotassiumrainstorm
antiserumbarnstormclassroomcolostrumcrossbeamdisesteemfetishismfirestormhailstormmaelstrompotassiumrainstormsandstormsnowstormtransformwindstormecdysiasmendospermendosteumequisetummisesteempressroomsalesroomclaustrumcolosseumvasospasm

About this list

Words
26 (16 common words)
Common example
antiserum
Rare example
vasospasm
Doubled letters
8
Ending in S
0
Most frequent letter
O (19)

Questions

How many 9-letter words matching ____s___m are there?

26. 16 of them are common words.

What is a common example?

ANTISERUM is among the common words in this set.