What are the uses of the ciborium?
The Ciborium is a metal vessel similar to a chalice but having a cover in which the host is contained and reserved in the tabernacle.
The container that actually holds the eucharist is called a ciborium, it resembles the chalice except it has a lid usually topped with a cross, dove, or image of christ. The eucharist is distributed from the ciborium. The container in which the ciborium is reserved is called a tabernacle. The glass disc that contains a large host for adoration is called a Luna, and is kept in a round container called a capsula, the Luna…
He uses bread and wine which he changes into the body and blood of Jesus Christ in remembrance of the Lamb of God, Jesus Christ, who at the Last Supper fulfilled the day of Unleavened Bread on which the Passover lamb had to be sacrificed in the Old Law. the priest uses a chalice and ciborium. he also uses the paten. a tabernacle also is used.
I am tempted to say the priest, but you are asking about a thing. The thing that the Host rests on when it is consecrated is a paten. The thing that the Host rests in when it is in the tabernacle is a ciborium. The thing that the Host is displayed in is an ostensorium or monstrance. You didn't specify which "thing".