10-Letter Words Matching _____S__M_

There are 19 10-letter words that match _____S__M_. 10 are common words, such as ECOSYSTEMS and FORTISSIMO. A rarer one is PROTOSTOME. In this set, S is the most frequent open letter (16 words). 9 words contain a doubled letter.

Full list 19

ecosystemsfortissimogymnasiumsmagnesiumspianissimipianissimopotassiumssolipsismssubsystemssymposiumsbravissimocyclostomelentissimosargassumsantiasthmacolosseumsfortissiminonsystemsprotostome

About this list

Words
19 (10 common words)
Common example
ecosystems
Rare example
protostome
Doubled letters
9
Ending in S
10
Most frequent letter
S (16)

Questions

How many 10-letter words matching _____s__m_ are there?

19. 10 of them are common words.

What is a common example?

ECOSYSTEMS is among the common words in this set.