What is the crossword answer for the clue: Certain Greek letters

NUS - a 3 letter word may be the answer you are looking for!

CHIS - a 4 letter word may be the answer you are looking for!

PHIS - a 4 letter word may be the answer you are looking for!

PSIS - a 4 letter word may be the answer you are looking for!

Certain Greek letters

3 Character Answers:

NUS

4 Character Answers:

CHIS

PHIS

PSIS