15-Letter Words Matching ____E____R_____

There are 12 15-letter words that match ____E____R_____. 2 are common words, such as BROKENHEARTEDLY and PREREGISTRATION. A rarer one is POLYELECTROLYTE. In this set, E is the most frequent open letter (11 words). 1 words contain a doubled letter.

Full list 12

brokenheartedlypreregistrationhousemistressespyroelectricitytenderheartedlydiphenhydraminemisregistrationoptoelectronicsoverelaboratingoverelaborationoverencouragingpolyelectrolyte

About this list

Words
12 (2 common words)
Common example
brokenheartedly
Rare example
polyelectrolyte
Doubled letters
1
Ending in S
2
Most frequent letter
E (11)

Questions

How many 15-letter words matching ____e____r_____ are there?

12. 2 of them are common words.

What is a common example?

BROKENHEARTEDLY is among the common words in this set.