15-Letter Words Matching ___R________R__

There are 16 15-letter words that match ___R________R__. 1 are common words, such as INFRASTRUCTURES and HYDROMETALLURGY. A rarer one is ULTRASTRUCTURES. In this set, A is the most frequent open letter (15 words). 3 words contain a doubled letter.

Full list 16

infrastructureshydrometallurgyinfrastructuralintramuscularlychordamesodermsextracellularlyintracellularlyintravascularlymacrostructuralmacrostructuresmicrostructuralmicrostructuressporangiophorestetrahydrofuranultrastructuralultrastructures

About this list

Words
16 (1 common words)
Common example
infrastructures
Rare example
ultrastructures
Doubled letters
3
Ending in S
6
Most frequent letter
A (15)

Questions

How many 15-letter words matching ___r________r__ are there?

16. 1 of them are common words.

What is a common example?

INFRASTRUCTURES is among the common words in this set.