15-Letter Words Matching _____A____R____

There are 13 15-letter words that match _____A____R____. 3 are common words, such as MOUNTAINEERINGS and NONTRANSFERABLE. A rarer one is XERORADIOGRAPHY. In this set, O is the most frequent open letter (12 words). 4 words contain a doubled letter.

Full list 13

mountaineeringsnontransferableseptuagenarianscrystallographyautoradiographsmonosaccharidespolysaccharidesautoradiographychemoautotrophyphotoautotrophsradioautographsradioautographyxeroradiography

About this list

Words
13 (3 common words)
Common example
mountaineerings
Rare example
xeroradiography
Doubled letters
4
Ending in S
7
Most frequent letter
O (12)

Questions

How many 15-letter words matching _____a____r____ are there?

13. 3 of them are common words.

What is a common example?

MOUNTAINEERINGS is among the common words in this set.