12-Letter Words Matching M_____H_____

There are 20 12-letter words that match M_____H_____. 6 are common words, such as MELANCHOLIAS and MELANCHOLIES. A rarer one is MOTHERHOUSES. In this set, O is the most frequent open letter (16 words). 6 words contain a doubled letter.

Full list 20

melancholiasmelancholiesmisanthropesmisanthropicmonarchisticmuddleheadedmelancholicsmacrophysicsmassotherapymelancholiacmenorrhagiasmerrythoughtmessiahshipsmicrophysicsmoneychangermultichannelmicrophonicsmisemphasizemonorchidismmotherhouses

About this list

Words
20 (6 common words)
Common example
melancholias
Rare example
motherhouses
Doubled letters
6
Ending in S
10
Most frequent letter
O (16)

Questions

How many 12-letter words matching m_____h_____ are there?

20. 6 of them are common words.

What is a common example?

MELANCHOLIAS is among the common words in this set.