12-Letter Words Matching I________U__

There are 12 12-letter words that match I________U__. 2 are common words, such as INTELLECTUAL and INTERREGNUMS. A rarer one is INTERSTIMULI. In this set, T is the most frequent open letter (12 words). 3 words contain a doubled letter.

Full list 12

intellectualinterregnumsichthyosaursinexactitudeinterlingualintermixtureintertextureichthyofaunainterboroughintercultureinterdiffuseinterstimuli

About this list

Words
12 (2 common words)
Common example
intellectual
Rare example
interstimuli
Doubled letters
3
Ending in S
2
Most frequent letter
T (12)

Questions

How many 12-letter words matching i________u__ are there?

12. 2 of them are common words.

What is a common example?

INTELLECTUAL is among the common words in this set.