9-Letter Words Matching ______S_A

There are 20 9-letter words that match ______S_A. 3 are common words, such as ANALGESIA and DYSPEPSIA. A rarer one is PHANTASMA. In this set, I is the most frequent open letter (17 words). 2 words contain a doubled letter.

Full list 20

analgesiadyspepsiajinrikshaartemisiaathanasiacollinsiadyscrasiadysphasiadysplasiaeclampsiaframbesiarafflesiaachalasiaanaplasiaayahuascahibakushananoteslaneoplasiaperimysiaphantasma

About this list

Words
20 (3 common words)
Common example
analgesia
Rare example
phantasma
Doubled letters
2
Ending in S
0
Most frequent letter
I (17)

Questions

How many 9-letter words matching ______s_a are there?

20. 3 of them are common words.

What is a common example?

ANALGESIA is among the common words in this set.