eight•y-firstPronunciation: (ā'tē fûrst'), [key]
next after the eightieth; being the ordinal number for 81.
being one of 81 equal parts.
an eighty-first part, esp. of one (1/81
the eighty-first member of a series.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.