The Collaborative International Dictionary of English v.0.48:

Holy cross \Ho"ly cross"\ (?; 115).
   The cross as the symbol of Christ's crucifixion.
   [1913 Webster]

   Congregation of the Holy Cross (R. C. Ch.), a community of
      lay brothers and priests, in France and the United States,
      engaged chiefly in teaching and manual Labor. Originally
      called Brethren of St. Joseph. The Sisters of the Holy
      Cross engage in similar work. --Addis & Arnold.

   Holy-cross day, the fourteenth of September, observed as a
      church festival, in memory of the exaltation of our
      Savior's cross.
      [1913 Webster]