Answer:

sigmas

Answer	Crossword Clue
SIGMAS	Sibilants for Socrates
SIGMAS	E-shaped letters
SIGMAS	Odysseus trio, to Homer

SIGMAS	Greek consonants
SIGMAS	Greek letters
SIGMAS	Fraternity letters
SIGMAS	Sum symbols in math
SIGMAS	Greek letters.
SIGMAS	Letters from Greece
SIGMAS	Summation signs
SIGMAS	Sorority letters

SIGMAS	Symbols in calculus

Crossword

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