Answer:

phis

Answer	Crossword Clue
PHIS	Letters from Athens
PHIS	Greek letters
PHIS	Upsilons' followers

PHIS	Frat letters
PHIS	Fraternity letters
PHIS	They follow upsilons
PHIS	Letters from Greece
PHIS	Sorority letters
PHIS	Key letters
PHIS	Greek consonants
PHIS	Greek letters.

PHIS	After upsilons
PHIS	Letters from Lemnos
PHIS	Chi preceders
PHIS	Greek characters
PHIS	Letters from Crete
PHIS	Diameter symbols, in math
PHIS	Letters after upsilons
PHIS	Certain Greek letters

PHIS	Latitude indicators
PHIS	Letters used by Pythagoras
PHIS	Some college Greeks

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.