13-Letter Words Matching __O______O___

There are 22 13-letter words that match __O______O___. 5 are common words, such as PROGESTERONES and PROPOSITIONAL. A rarer one is ZOOPLANKTONIC. In this set, O is the most frequent open letter (18 words). 3 words contain a doubled letter.

Full list 22

progesteronespropositionalpropositionedthoroughgoingtroubleshootsbronchoscopeschondriosomesisoelectronicphotocathodesphotocomposerprocreationalthoroughwortsbronchoscopicgeohydrologicphotobiologicphotocomposedphotocomposesphotogeologicphotoperiodicprogressionalprotohistoriczooplanktonic

About this list

Words
22 (5 common words)
Common example
progesterones
Rare example
zooplanktonic
Doubled letters
3
Ending in S
7
Most frequent letter
O (18)

Questions

How many 13-letter words matching __o______o___ are there?

22. 5 of them are common words.

What is a common example?

PROGESTERONES is among the common words in this set.