Answer:

PHI

AnswerCrossword Clue
PHISorority letter
PHIHonor-society letter
PHI.. Beta Kappa
PHIFrat letter
PHIUpsilon follower
PHILetter before chi
PHIGreek consonant
PHILetter after upsilon
PHISweater letter
PHIThe Sixers' PA home
PHIThe Golden Ratio
PHIGolden Ratio symbol
PHI... Bete (honor-society member, for short)
PHIKey letter
PHI... Beat Kappa
PHI... Beta Kappa
PHILetter on a key
PHI.. Bete: elite society member
PHIN.L. East team, on scoreboards
PHIEuler's .. function
PHI.. Bete
PHIChi follows it
PHILetter from Pharos
PHI21st Greek letter
PHISixers, on a scoreboard
PHIEagles, on scoreboards
PHIChi preceder
PHILetter between upsilon and chi
PHIPart of PBK
PHIGolden ratio symbol
PHINYG NFL rival
PHIFraternity letter
PHIHonor society letter
PHIGreek F
PHICollege letter
PHILetter voiced by a Greek giant?
PHIFraternal letter
PHIGreek letter
PHIUpsilon's successor
PHIUpsilon's follower