12-Letter Words Matching T_T_________

There are 18 12-letter words that match T_T_________. 7 are common words, such as TETRACYCLINE and TETRAHEDRONS. A rarer one is TITANIFEROUS. 4 words contain a doubled letter.

Full list 18

tetracyclinetetrahedronstitillationstitleholderstotalisatorstotalitariantotalizatorstetrapteroustetanizationtetchinessestetradrachmstetragonallytetrahedritetetrahymenastetrapyrroletetrazoliumstetrodotoxintitaniferous

About this list

Words
18 (7 common words)
Common example
tetracycline
Rare example
titaniferous
Doubled letters
4
Ending in S
11

Questions

How many 12-letter words matching t_t_________ are there?

18. 7 of them are common words.

What is a common example?

TETRACYCLINE is among the common words in this set.