Meaning of Gregorian water

Grego'rian wa'ter

Pronunciation: [key]
— Rom. Cath. Ch. Rom. Cath. Ch.
  1. a mixture of water, salt, ashes, and wine, blessed and sprinkled over the altar in the consecration of a church.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.