12-Letter Words Matching D_____M_____

There are 21 12-letter words that match D_____M_____. 5 are common words, such as DEPARTMENTAL and DIAGRAMMATIC. A rarer one is DYSPHEMISTIC. In this set, I is the most frequent open letter (19 words). 6 words contain a doubled letter.

Full list 21

departmentaldiagrammaticdiscommodingdiscriminatedisharmoniesdiscriminantdepolymerizedesquamatingdiagrammabledichromatismdisclamationdiscommoditydynamometersdesquamationdilatometersdilatometricdiscommendeddisharmonizedissymmetricdynamometricdysphemistic

About this list

Words
21 (5 common words)
Common example
departmental
Rare example
dysphemistic
Doubled letters
6
Ending in S
3
Most frequent letter
I (19)

Questions

How many 12-letter words matching d_____m_____ are there?

21. 5 of them are common words.

What is a common example?

DEPARTMENTAL is among the common words in this set.