fif•ty-fifthPronunciation: (fif'tē fifth' or, often, -fith'), [key]
next after the fifty-fourth; being the ordinal number for 55.
being one of 55 equal parts.
a fifty-fifth part, esp. of one (1/55
the fifty-fifth member of a series.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.