Monstrance at Benediction - Catholic Stock Photo

A monstrance, also known as an ostensorium (or an ostensory), is a vessel used in Roman Catholic churches to display some object of piety, such as the consecrated Eucharistic host during Eucharistic adoration or Benediction of the Blessed Sacrament, on an altar. It is also used as a reliquary for the public display of some saints' relics. The term monstrance is derived from the Latin word monstrare, whereas the term ostensorium is derived from the Latin word ostendere. Both terms, which mean "to show," are used for vessels intended for the exposition of the Blessed Sacrament, but ostensorium only means "to show."