15-Letter Words Matching ____A______U___

There are 12 15-letter words that match ____A______U___. 3 are common words, such as EXTRACURRICULAR and INFRASTRUCTURES. A rarer one is WELTANSCHAUUNGS. In this set, T is the most frequent open letter (11 words). 2 words contain a doubled letter.

Full list 12

extracurricularinfrastructuresinstantaneouslydisharmoniouslyinfrastructuraloverambitiouslypremanufacturedpremanufacturestetrahydrofuranultrastructuralultrastructuresweltanschauungs

About this list

Words
12 (3 common words)
Common example
extracurricular
Rare example
weltanschauungs
Doubled letters
2
Ending in S
4
Most frequent letter
T (11)

Questions

How many 15-letter words matching ____a______u___ are there?

12. 3 of them are common words.

What is a common example?

EXTRACURRICULAR is among the common words in this set.