15-Letter Words Matching ____O________R_

There are 13 15-letter words that match ____O________R_. 2 are common words, such as MICROPROCESSORS and NONCONTRIBUTORY. A rarer one is TURBOGENERATORS. In this set, R is the most frequent open letter (12 words). 2 words contain a doubled letter.

Full list 13

microprocessorsnoncontributoryneuropsychiatrynitrochloroformorthopsychiatrymicrophotometrymicroprojectorsmicropublishersneurofibrillarynoncontemporaryretroreflectorsschlockmeistersturbogenerators

About this list

Words
13 (2 common words)
Common example
microprocessors
Rare example
turbogenerators
Doubled letters
2
Ending in S
6
Most frequent letter
R (12)

Questions

How many 15-letter words matching ____o________r_ are there?

13. 2 of them are common words.

What is a common example?

MICROPROCESSORS is among the common words in this set.