I am reading about Titus Flavius Sabinus (consul AD 47) and cannot find meaning of T. f. T. n. in his full name as written in Wikipedia, "Titus Flavius T. f. T. n. Sabinus."
All I have found is a list of roman consuls and military tribunes where similar abbreviations are used with various letters.
Searching for TFTN or T. f. T. n. returns modern abbreviations like "Thanks For The Numbers," "The Free Times Newspaper," nothing relevant.
Reading the wiki page history I see no indication why this abbreviation was inserted.
My guess would be T. f. T. n. is abbreviation of province or military regiment?