Answer: xis

AnswerCrossword Clue
XISNumbers or letters
xisthe 14th letter of the Greek alphabet see alphabet table
xisXI, the fourteenth letter of the Greek alphabet
xisthe 14th letter of the Greek alphabet
XISSome fraternity row letters
XISLetters between nus and omicrons
XISThey follow nus
XISNu followers
XISLetters after nus
XISGreek letters after nus
XISCharacters from Sophocles
XISGreek characters
XISLetters from Xanthippe
XISOmicrons' predecessors
XISAttic letters
XISLetters from Greece
XISGreek letters
XISBefore omicrons
XISGreek letters.
XISSorority letters
XISExpected 2015 Sue Grafton title starter
XISFrat letters
XISOmicron preceders
XISFraternity letters
XISFirst words of the title of Sue Grafton's as-yet-unwritten 24th Kinsey Millhone mystery
XISNus' successors
XISThey precede omicrons
XISLetters before omicrons
XISFollowers of nus
XISOmicrons' preceders
XISGreek consonants
XISThey follow the nus