Crossword Clue:

KOPPA a Greek letter

Answer	Crossword Clue
TAU	A Greek letter
STICKINTHEMU	Add a Greek letter?
PICKSUPTHETA	Lifts a Greek letter?

PHI	Greek letter on a key
PHI	Letter voiced by a Greek giant?
OMEGA	Greek letter shaped like a horseshoe
TAKESITONTHECHI	Endures hardship atop a Greek letter?
TAU	Greek letter shaped like a cross
DELTA	Airline whose name is a Greek letter
PSI	Greek letter that looks like a pitchfork
RHO	Greek letter that looks like a "P"

WORNDOWNTOTHENU	Eroded as far as a Greek letter?
PSI	Greek letter that looks like a trident
ETA	Greek letter that's a symbol for viscosity
RHO	Greek letter that looks like a P
RHO	Greek letter whose capital looks like a P
GNU	Animal whose name sounds like a Greek letter
PSI	Greek letter that begins with a silent letter
PSI	Greek letter that sounds like a deep breath

THETA	Greek letter with a line through its middle
RHO	Greek letter that's a homophone of two English words
BEETS	Vegetables whose genus shares its name with a Greek letter
PSI	Greek letter spelled out at the start of a Beatles title?
ETA	Greek letter
CHI	Greek letter
KAPPA	Greek letter.
OMEGA	Greek letter

CHI	Greek letter.
IOTA	Greek letter
IOTA	Greek letter.
EPSILON	Greek letter
DELTA	Greek letter.
LAMBDA	Greek letter
THETA	Greek letter
KAPPA	Greek letter

IONIANEPISTLE	Greek letter
PHI	Greek letter
SIGMA	Greek letter.
ZETA	Greek letter.
PHI	Greek letter.