12-Letter Words Matching ________S_A_

There are 18 12-letter words that match ________S_A_. 5 are common words, such as ANAESTHESIAS and ANTIMACASSAR. A rarer one is STERNOCOSTAL. In this set, I is the most frequent open letter (14 words). 2 words contain a doubled letter.

Full list 18

anaesthesiasantimacassarbackwoodsmanfashionistasfrontiersmanbacteriostathyperplasiaskinesthesiasparesthesiassupersensualsynesthesiasantonomasiashypermnesiasintercoastalmicrocrystalparonomasiasplasmodesmassternocostal

About this list

Words
18 (5 common words)
Common example
anaesthesias
Rare example
sternocostal
Doubled letters
2
Ending in S
10
Most frequent letter
I (14)

Questions

How many 12-letter words matching ________s_a_ are there?

18. 5 of them are common words.

What is a common example?

ANAESTHESIAS is among the common words in this set.