12-Letter Words Matching O__O________

There are 22 12-letter words that match O__O________. 7 are common words, such as OBSOLESCENCE and OCTOGENARIAN. A rarer one is OUTORGANIZES. In this set, I is the most frequent open letter (19 words). 10 words contain a doubled letter.

Full list 22

obsolescenceoctogenarianodiousnessesoleomargarinopportunismsopportunistsoptometristsobsoletenessoctosyllabicoctosyllableoenophilistsoncogenicityopposabilityoppositenessoppositionaloleoresinousoncornavirusosmolalitiesosmolaritiesotiosenessesoutorganizedoutorganizes

About this list

Words
22 (7 common words)
Common example
obsolescence
Rare example
outorganizes
Doubled letters
10
Ending in S
13
Most frequent letter
I (19)

Questions

How many 12-letter words matching o__o________ are there?

22. 7 of them are common words.

What is a common example?

OBSOLESCENCE is among the common words in this set.