15-Letter Words Matching __R__T_________

There are 18 15-letter words that match __R__T_________. 4 are common words, such as FORGETFULNESSES and MARKETABILITIES. A rarer one is VERSATILENESSES. 12 words contain a doubled letter.

Full list 18

forgetfulnessesmarketabilitiesparentheticallystraitjacketingdermatoglyphicsgyrostabilizersperistalticallystreptothricinscarpetbaggeriesnormativenessesstraitlacednessstreptobacillusstructuralizingterritorialismsterritorialiststerritorializedterritorializesversatilenesses

About this list

Words
18 (4 common words)
Common example
forgetfulnesses
Rare example
versatilenesses
Doubled letters
12
Ending in S
13

Questions

How many 15-letter words matching __r__t_________ are there?

18. 4 of them are common words.

What is a common example?

FORGETFULNESSES is among the common words in this set.