Answer:

ZETA

Answer	Crossword Clue
ZETA	Sixth Greek letter
ZETA	Dionne Warwick or Zora Neale Hurston, sorority-wise
ZETA	Epsilon follower

ZETA	Epsilon's follower
ZETA	Greek consonant
ZETA	Letter after epsilon
ZETA	Greek letter
ZETA	Riemann ... function
ZETA	... Phi Beta (sorority founded at Howard University)
ZETA	Greek sleeper's letter?
ZETA	Sweater letter

ZETA	Sixth in a series
ZETA	Actress Catherine ..-Jones
ZETA	Sixth of 24
ZETA	Catherine ..-Jones
ZETA	Letter on a sweater
ZETA	Greek letter that seems like it should be last
ZETA	Second of four rhyming Greek letters
ZETA	Zeus' beginning?

ZETA	It follows epsilon
ZETA	Bit of sound from a Greek snorer?
ZETA	Sorority letter
ZETA	Actress Catherine ...-Jones
ZETA	Greek Z
ZETA	Catherine ...-Jones
ZETA	Fraternity letter
ZETA	It's both sixth and last, alphabetically

ZETA	Bit of a snore in Greece?
ZETA	Predecessor of eta
ZETA	Zeus starter?
ZETA	Letter that rhymes with its two successors
ZETA	Certain sorority chapter
ZETA	Oscar winner Catherine ...-Jones
ZETA	Greek letter in an actress's name
ZETA	Letter from Zeno?

ZETA	Greek "Z"
ZETA	Actress Catherine ... Jones
ZETA	Greek letter that would be last in English
ZETA	Catherine .. Jones of "The Mask of Zorro"
ZETA	Z