'Lady Day' definitions:

Definition of 'Lady Day'

(from WordNet)
noun
A festival commemorating the announcement of the Incarnation by the angel Gabriel to the Virgin Mary; a quarter day in England, Wales, and Ireland [syn: Annunciation, Lady Day, Annunciation Day, March 25]

Definition of 'Lady Day'

From: GCIDE
  • Lady Day \La"dy` Day`\ (d[=a]) n. The day of the annunciation of the Virgin Mary, March 25. See Annunciation. [1913 Webster]