Definition of "monstrance"
(Christianity) An ornamental, often precious receptacle, either open or with a transparent cover, in which the sacramental bread (consecrated host) is placed for Eucharistic adoration.
Quotations
He loved to kneel down on the cold marble pavement and watch the priest, in his stiff flowered dalmatic, slowly and with white hands moving aside the veil of the tabernacle, or raising aloft the jewelled, lantern-shaped monstrance with that pallid wafer that at times, one would fain think, is indeed the "panis caelestis," the bread of angels, or, robed in the garments of the Passion of Christ, breaking the Host into the chalice and smiting his breast for his sins.
1891, Oscar Wilde, The Picture of Dorian Gray, London, New York, N.Y., Melbourne, Vic.: Ward Lock & Co.